Power system for high temperature applications with rechargeable energy storage

ABSTRACT

A power system adapted for supplying power in a high temperature environment is disclosed. The power system includes a rechargeable energy storage that is operable in a temperature range of between about seventy degrees Celsius and about two hundred and fifty degrees Celsius coupled to a circuit for at least one of supplying power from the energy storage and charging the energy storage; wherein the energy storage is configured to store between about one one hundredth (0.01) of a joule and about one hundred megajoules of energy, and to provide peak power of between about one one hundredth (0.01) of a watt and about one hundred megawatts, for at least two charge-discharge cycles. Methods of use and fabrication are provided. Embodiments of additional features of the power supply are included.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is filed under 35 U.S.C. §111(a) and claims priorityunder 35 U.S.C. §120 to U.S. patent application Ser. No. 12/928,896,entitled “Electrochemical Double Layer Capacitor for High Temperature,”filed Dec. 21, 2010; also claiming priority under 35 U.S.C. §119(e) toU.S. Provisional Patent Application Nos. 61/489,389 filed May 24, 2011;61/493,039 filed Jun. 3, 2011; 61/494,332 filed Jun. 7, 2011; 61/537,360filed Sep. 21, 2011; and 61/620,364 filed Apr. 4, 2012, the entiredisclosures of which are incorporated by reference herein in theirentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to methods and apparatus for providing power in ahigh temperature environment, in particular, for instrumentation andtooling used in subsurface environments generally in the exploration forhydrocarbons.

2. Description of the Related Art

As mankind continues to search for and extract oil, the quest forhydrocarbons has grown increasingly complex. This complexity has givenrise to all sorts of complicated instrumentation. Consistent with othersegments of technology, increasing complexity of instrumentationpresents users with increasing power demands.

Unfortunately, the downhole environment presents real and unavoidableproblems for system owners and operators. For example, and of no smallconsequence, are problems that arise with downhole temperatures. Thatis, as well drilling and logging plunges ever deeper into the Earth'scrust, the exposure of downhole tooling to high temperature environmentscontinues to increase.

The increased temperature can often present technical limitations whenconventional power supplies fail. For example, when chemically basedbattery storage is essentially degraded to the point of losingfunctionality.

Thus, what is needed is a power system for supplying power in hightemperature environments. Preferably, the power system includesrechargeable energy storage that provides users with power whereconventional devices will fail to provide useful power. Further, it ispreferred that the energy storage device be economic to use, handle anddisposition.

BRIEF SUMMARY OF INVENTION

In one embodiment, a power system adapted for supplying power in a hightemperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage, wherein theenergy storage is configured to store between about one one hundredth(0.01) of a joule and about one hundred megajoules of energy, and toprovide peak power of between about one one hundredth (0.01) of a wattand about one hundred megawatts, for at least two charge-dischargecycles.

In another embodiment, a method for providing power to a logginginstrument downhole is provided. The method includes selecting a logginginstrument that includes a power system including a rechargeable energystorage that is operable in a temperature range of between about minusforty degrees Celsius and two hundred and ten degrees Celsius coupled toa circuit for at least one of supplying power from the energy storageand charging the energy storage; and with the logging instrumentdownhole, providing power from the power system to the logginginstrument.

In another embodiment, a method for fabricating a power system for alogging instrument is provided. The method includes selecting arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; and configuringthe energy storage for incorporation into the logging instrument.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for depassivation of a battery in theenergy storage.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for simulating electrical output of anenergy supply.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for monitoring a state of charge of theenergy storage.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for switching among at least two sources ofenergy.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for automatically adjusting a voltageoutput of the power system.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for switching between modes of operation.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for adjusting operation according to anenvironmental factor.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty eventy degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for inducing low-power operation.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for logging data.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for managing performance of the powersupply.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for monitoring health of the power system.

In another embodiment, a power system adapted for supplying power in ahigh temperature environment is provided. The power system includes arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit includes a subsystem for accessing redundant elements.

In another embodiment, a method using a power supply is provided. Themethod includes selecting a power supply that has at least oneultracapacitor; and operating the power supply within a temperaturerange of between about minus forty degrees Celsius and about two hundredand ten degrees Celsius while maintaining a voltage of between about 0.1Volts to about 4 Volts on the ultracapacitor for at least one hour;wherein, at the end of the hour, the ultracapacitor exhibits a leakagecurrent less than 1,000 mAmp per liter of volume over the range ofoperating temperature.

In yet another embodiment, a method of using a power system is provided.The method includes coupling a rechargeable energy storage configuredfor high temperature operation with electronics configured for hightemperature operation; and operating the power system by withdrawingpulses of power from an output of the power system, wherein each pulsescomprises a peak value of at least 0.01 W and a total power-time product(energy) of at least 0.01 J.

BRIEF DESCRIPTION OF DRAWINGS

The features and advantages of the invention are apparent from thefollowing description taken in conjunction with the accompanyingdrawings in which:

FIG. 1 illustrates an exemplary embodiment of a drill string thatincludes a logging instrument;

FIG. 2 illustrates an exemplary embodiment for well logging with anembodiment of the logging instrument deployed by a wireline;

FIG. 3 illustrates an exemplary embodiment of a producing well with anembodiment of the logging instrument deployed therein;

FIG. 4 is a schematic view of aspects of an exemplary rechargeableenergy storage that includes a single storage cell, the cell being anelectrolytic double layer capacitor, EDLC, and suited for use as a hightemperature energy storage;

FIG. 5 illustrates an embodiment of a topology of a power system thatincludes a high temperature rechargeable energy storage;

FIGS. 6-8 illustrate aspects of the topology of FIG. 5;

FIG. 9 illustrates another embodiment of a topology for a power systemthat includes high temperature rechargeable energy storage;

FIG. 10 is a block diagram depicting one embodiment of a battery voltagesimulator;

FIGS. 11A and 11B, collectively referred to herein as FIG. 11, are blockdiagrams depicting a parallel embodiment and a series embodiment of abattery voltage simulator, respectively;

FIGS. 12-14 are block diagrams depicting embodiments of a converter forthe voltage simulator of FIGS. 10 and 11;

FIG. 15 is a block diagram depicting an embodiment of a feedbackcontroller for the voltage simulator of FIGS. 10 and 11;

FIG. 16 is a diagram that depicts aspects of a state of charge monitor;

FIG. 17 is a diagram that depicts aspects of a change over control unit;

FIGS. 18A, 18B and 18C, collectively referred to herein as FIG. 18, areblock diagrams depicting embodiments of a bypass controller;

FIG. 19 is a perspective view of an exemplary power supply;

FIG. 20 is an exploded view of the power supply of FIG. 19;

FIG. 21 is a perspective view of a controller for the power supplyillustrated in FIGS. 19 and 20;

FIG. 22 is a side view of circuits that are assembled using busconnectors;

FIG. 23 is an isometric view of a storage cell; and,

FIGS. 24A and 24B, collectively referred to herein as FIG. 24, areisometric views of two of the storage cells of FIG. 23 in stages ofassembly into the energy storage

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein is a power system that provides electrical energy in ahigh temperature environment. In addition to providing electrical energyin a high temperature environment, the power system may be configured toprovide users with a variety of additional functions. While embodimentsof the power system presented herein are configured for use in adownhole (i.e., subterranean) environment, it should be recognized thatthe power system may be used equally well in high temperatureenvironments that present challenges to provision of reliable power.Such challenges may include environmentally harsh conditions, limitedspace available for containing energy storage, a substantially remotelocation where it is difficult to communicate with external powersupplies and the like. Prior to introducing the power system in greaterdetail, some context is provided.

Refer now to FIG. 1 where aspects of an apparatus for drilling awellbore 1 (also referred to as a “borehole”) are shown. As a matter ofconvention, a depth of the wellbore 1 is described along a Z-axis, whilea cross-section is provided on a plane described by an X-axis and aY-axis.

In this example, the wellbore 1 is drilled into the Earth 2 using adrill string 11 driven by a drilling rig (not shown) which, among otherthings, provides rotational energy and downward force. The wellbore 1generally traverses sub-surface materials, which may include variousformations 3 (shown as formations 3A, 3B, 3C). One skilled in the artwill recognize that the various geologic features as may be encounteredin a subsurface environment may be referred to as “formations,” and thatthe array of materials down the borehole (i.e., downhole) may bereferred to as “sub-surface materials.” That is, the formations 3 areformed of sub-surface materials. Accordingly, as used herein, it shouldbe considered that while the term “formation” generally refers togeologic formations, and “sub-surface material,” includes any materials,and may include materials such as solids, fluids, gases, liquids, andthe like.

In this example, the drill string 11 includes lengths of drill pipe 12which drive a drill bit 14. The drill bit 14 also provides a flow of adrilling fluid 4, such as drilling mud. The drilling fluid 4 is oftenpumped to the drill bit 14 through the drill pipe 12, where the fluidexits into the wellbore 1. This results in an upward flow, F, ofdrilling fluid 4 within the wellbore 1. The upward flow generally coolsthe drill string 11 and components thereof, carries away cuttings fromthe drill bit 14 and prevents blowout of pressurized hydrocarbons 5.

The drilling fluid 4 (also referred to as “drilling mud”) generallyincludes a mixture of liquids such as water, drilling fluid, mud, oil,gases, and formation fluids as may be indigenous to the surroundings.Although drilling fluid 4 may be introduced for drilling operations, useor the presence of the drilling fluid 4 is neither required for nornecessarily excluded from well logging operations. Generally, a layer ofmaterials will exist between an outer surface of the drill string 11 anda wall of the wellbore 1. This layer is referred to as a “standofflayer,” and includes a thickness, referred to as “standoff, S.”

The drill string 11 generally includes equipment for performing“measuring while drilling” (MWD), also referred to as “logging whiledrilling” (LWD). Performing MWD or LWD generally calls for operation ofa logging instrument 10 that is incorporated into the drill string 11and designed for operation while drilling. Generally, the logginginstrument 10 for performing MWD is coupled to an electronics packagewhich is also on board the drill string 11, and therefore referred to as“downhole electronics 13.” Generally, the downhole electronics 13provide for at least one of data collection, data analysis, andoperational control such as electromechanical actuation (s),communications, power processing and the like. A power system 16 may beincluded. Generally, the power system 16 powers at least one of thelogging instrument 10, survey components 15 and the downhole electronics13. Often, the logging instrument 10 and the downhole electronics 13 arecoupled to topside equipment 7. The topside equipment 7 may be includedto further control operations, provide greater analysis capabilities aswell as data logging and the like. A communications channel (discussedbelow) may provide for communications to the topside equipment 7, andmay operate via pulsed mud, wired pipe, EM telemetry, fiber optic andother technologies as are known in the art and are practicable for agiven application.

Referring now to FIG. 2, an exemplary logging instrument 10 for wirelinelogging of the wellbore 1 is shown. As a matter of convention, a depthof the wellbore 1 is described along a Z-axis, while a cross-section isprovided on a plane described by an X-axis and a Y-axis. Prior to welllogging with the logging instrument 10, the wellbore 1 is drilled intothe Earth 2 using a drilling apparatus, such as the one shown in FIG. 1.

In some embodiments, the wellbore 1 has been filled, at least to someextent, with drilling fluid 4. The drilling fluid 4 (also referred to as“drilling mud”) generally includes a mixture of liquids such as water,drilling fluid, mud, oil, gases, and formation fluids as may beindigenous to the surroundings. Although drilling fluid 4 may beintroduced for drilling operations, use or the presence of the drillingfluid 4 is neither required for nor necessarily excluded from loggingoperations during wireline logging. Generally, a layer of materials willexist between an outer surface of the logging instrument 10 and a wallof the wellbore 1. This layer is referred to as a “standoff layer,” andincludes a thickness, referred to as “standoff, S.”

A casing 21 may be inserted into the wellbore 1 to ensure physicalintegrity. The casing may be formed in the wellbore 1, inserted therein,or otherwise disposed in the wellbore 1. The casing 21 may be segmentedor continuous. For purposes of discussion herein, the casing 21generally includes various installations of cementatious outer casing21, as well as inner production tubing (such as production tubing).

Generally, in wireline logging, the logging instrument 10 is loweredinto the wellbore 1 using a wireline 8 deployed by a derrick 6 orsimilar equipment. Generally, the wireline 8 includes suspensionapparatus, such as a load bearing cable, as well as other apparatus. Theother apparatus may include a power system, a communications link (suchas wired or optical) and other such equipment. Generally, the wireline 8is conveyed from a service truck 9 or other similar apparatus (such as aservice station, a base station, etc, . . . ). Often, the wireline 8 iscoupled to topside equipment 7. The topside equipment 7 may providepower to the logging instrument 10, as well as provide computing andprocessing capabilities for at least one of control of operations andanalysis of data.

Generally, the logging instrument 10 includes apparatus for performingmeasurements “downhole” or in the wellbore 1. Such apparatus include,for example, a variety of survey components 15. Exemplary surveycomponents 15 may include radiation detectors, shielding, sensors,transducers, and many of the other various survey components 15 known inthe art. The components 15 may communicate with downhole electronics 13as appropriate. The power system 16 may be included. Generally, thepower system 16 powers at least one of the logging instrument 10, surveycomponents 15 and downhole electronics 13. The measurements and othersequences as may be performed using the logging instrument 10 aregenerally performed to ascertain and qualify presence of hydrocarbons 5,but may be used for other purposes, such as to identify geothermalresources.

Referring now to FIG. 3, there is shown an exemplary logging instrument10 for logging during production. The production logging instrument 10may be deposited within the wellbore 1, where it will reside duringextraction of hydrocarbons 5. The production logging instrument 10 maybe deposited downhole by use of other equipment, such as a tractor (notshown). In some embodiments, the production logging instrument 10 mayinclude elements of a tractor (such as a motor and track). The powersystem 16 may be included. Generally, the power system 16 powers atleast one of the logging instrument 10, survey components 15 anddownhole electronics 13.

Once production is initiated, the drilling fluid 4 is expelled from thewellbore 1. A flow of the hydrocarbons 5 is established. Duringinitiation of production, a wellhead 19 is placed over the wellbore 1.The wellhead 19 provides for regulation of flow from the wellbore 1, andaccommodates extended periods of extraction of the hydrocarbons 5. Asshown by the upward arrow, when the production logging instrument 10 isin place, production (the withdrawal of hydrocarbons 5) may continueunabated. Generally, the wellhead 19 includes a blow-out preventer, asis known in the art.

Consider now to the power system 16 in more detail. In exemplaryembodiments, the power system 16 includes internal energy storage. Theenergy storage may include any one or more of a variety of forms ofrechargeable energy storage. For example, rechargeable energy storagemay include at least one type of battery, an ultracapacitor and othersimilar devices. Aspects of exemplary energy storage are now discussedin greater detail.

Note that the power system 16 may generally be any device that canaccept and supply power reliably at high temperature. Other exemplaryforms of energy storage 30 include chemical batteries, for instancealuminum electrolytic capacitors, tantalum capacitors, ceramic and metalfilm capacitors, hybrid capacitors magnetic energy storage, forinstance, air core or high temperature core material inductors. Othertypes of that may also be suitable include, for instance, mechanicalenergy storage devices, such as fly wheels, spring systems, spring-masssystems, mass systems, thermal capacity systems (for instance thosebased on high thermal capacity liquids or solids or phase changematerials), hydraulic or pneumatic systems. One example is the hightemperature hybrid capacitor available from Evans Capacitor CompanyProvidence, R.I. USA part number HC2D060122 DSCC10004-16 rated for 125degrees Celsius. Another example is the high temperature tantalumcapacitor available from Evans Capacitor Company Providence, R.I. USApart number HC2D050152HT rated to 200 degrees Celsius. Yet anotherexample is an aluminum electrolytic capacitor available from EPCOSMunich, Germany part number B41691A8107Q7, which is rated to 150 degreesCelsius. Yet another example is the inductor available from PanasonicTokyo, Japan part number ETQ-P5M470YFM rated for 150 degrees Celsius.Additional embodiments are available from Saft, Bagnolet, France (partnumber Li-ion VL 32600-125) operating up to 125 degrees Celsius with 30charge-discharge cycles, as well as a li-ion battery (experimental)operable up to about 250 degrees Celsius, and in experimental phase withSadoway, Hu, of Solid Energy in Cambridge, Mass.

The environment downhole is harsh and therefore presents considerablechallenges to reliability of equipment. For example, ambienttemperatures may range from those at the surface up to about 300 degreesCelsius and higher. As will be discussed further herein, in someembodiments, the power system 16 disclosed is configured to operate inenvironments where the ambient temperatures are in the range of aboutseventy (70) degrees Celsius up to about 200 degrees Celsius, and, insome embodiments, higher (for example, up to about 250 degrees Celsius).In some embodiments, the power system 16 may be operated in environmentswhere the ambient temperatures is as low as about minus forty (−40)degrees Celsius. However, it should be noted that the power system 16may operate in a wider temperature range, and therefore this temperaturerange is not limiting of the teachings herein.

As a matter of convention, and for purposes of the teachings herein, theterm “energy storage” refers to an energy storage device that willoperate in environments where increased temperature will cause aconventional energy storage device generally to fail. That is, theenergy storage will outperform the conventional energy storage devicewhen placed in an equivalent environment and provide at least somedegree of utility as a function of increasing temperature.

In general, ultracapacitors as provided and used according to theteachings herein provide numerous advantages over existing energystorage technology. These advantages result in an ability to provide anduse power at higher temperatures than previously achieved. Accordingly,as users of downhole tooling are provided with greater operating range,areas that were previously out of reach as a result of power limitationsbecome accessible.

One set of advantages originates in the rechargeable nature of anultracapacitor. An ultracapacitor can both release and accept energy. Anultracapacitor may be used as a rechargeable energy storage device fordownhole applications. For example, an ultracapacitor may provide powerto the tool in a pulsed or intermittent fashion, but be recharged by awireline, downhole battery, or downhole generator in a more continuousfashion.

Another set of advantages originates in the high power handlingcapability of ultracapacitors. An ultracapacitor is well known toexhibit less internal resistance for similar volumes and weights whencompared to chemical battery energy storage technologies. Thischaracteristic enables higher power delivery capability when compared toprimary (non-rechargeable) chemical battery technologies and furtherhigher power recovery capability when compared to rechargeable chemicalbattery technologies. The ultracapacitor may be used to extend the powerhandling capability of an overall system. For example, an ultracapacitormay provide large pulses of power not available directly from typicalwireline, downhole battery, or downhole generator power deliverysystems.

Another set of advantages originates in the materials used to produce anultracapacitor. Because an ultracapacitor stores energy in electricfields rather than via chemical reactions, the materials themselves areless prone to catastrophic failures either by exposing those materialsto air environments or by using the energy storage device beyond israted capability. For example, an ultracapacitor may be used with littleor no augmentation of handling, safety and disposal logistics beyond theprocedures already in place to support downhole applications.Additionally, the use of an ultracapacitor in downhole applications mayreduce the need for other energy storage technology and in this casewould actually reduce the needed handling, safety and disposal logisticsrequired to support downhole applications.

Another set of advantages originates in the high energy density ofultracapacitors. An ultracapacitor can store about 50 to about 1,000times more energy than capacitors of comparable size and volume. Thisfeature enables the ultracapacitor to provide high power for a longerduration in downhole tools.

Ultracapacitors have never been suitable, before now, for uses indownhole tools due to their inability to operate at temperatures greaterthan about seventy degrees Celsius. Embodiments of exemplaryultracapacitors suited for the teachings herein solve problemsassociated with high temperature operation by being capable of reliableand safe operation in the harsh environments often encountered downhole.

More detail on exemplary embodiments of an ultracapacitor are nowprovided.

As shown in FIG. 4, an exemplary energy storage 30 includes at least onestorage cell 42. In this example, the energy storage 30 includes anelectrochemical double-layer capacitor (EDLC), also referred to as an“ultracapacitor.” The ultracapacitor includes two electrodes (referredto, by convention, as a “negative electrode” 33 and a “positiveelectrode” 34, however, the ultracapacitor need not have a charge storedtherein for purposes of this description), each electrode 33, 34 havinga double layer of charge at an electrolyte interface. In someembodiments, a plurality of electrodes is included. However, forpurposes of discussion, only two electrodes 33, 34 are shown. As amatter of convention herein, each of the electrodes 33, 34 use acarbon-based energy storage media 31 (as discussed further herein) toprovide energy storage.

Each of the electrodes 33, 34 includes a respective current collector32. The electrodes 33, 34 are separated by a separator 35. In general,the separator 35 is a thin structural material (usually a sheet) used toseparate the electrodes 33, 34, into two or more compartments.

At least one form of electrolyte 36 is included. The electrolyte 36fills void spaces in and between the electrodes 33, 34 and the separator35. In general, the electrolyte 36 is a substance that includeselectrically charged ions. A solvent that dissolves the substance may beincluded in some embodiments. A resulting electrolytic solution conductselectricity by ionic transport.

As a matter of convenience, a combination of the electrodes 33, 34, theseparator 35 and the electrolyte 36 are referred to as a “storage cell42.” In some embodiments, the term “storage cell” merely makes referenceto the electrodes 33, 34 and the separator 35 without the electrolyte36.

Generally, the exemplary EDLC is of a wound form which is then packagedinto a cylindrical enclosing housing 37 (which may be referred to simplyas the “housing 37”). Other forms, such as prismatic forms, may be used.The housing 37 may be hermetically sealed. In various examples, thepackage is hermetically sealed by techniques making use of laser,ultrasonic, and/or welding technologies. The housing 37 (also referredto as a “case”) includes at least one terminal 38. Each terminal 38provides electrical access to energy stored in the energy storage media31.

In some embodiments, the housing 37 is fabricated from at least onematerial that is selected to minimize reactivity with the electrolyte36. For example, the housing 37 may be fabricated from aluminum as wellas an alloy of aluminum. In some embodiments, other materials such astantalum may be used, at least in part (for example, as a terminal 38).

In the exemplary EDLC, the energy storage media 31 may be provided byand include activated carbon, carbon fibers, rayon, graphene, aerogel,carbon cloth, carbon nanotubes (such as single-walled and/ormulti-walled) and/or other carbon nanoforms. Activated carbon electrodesmay be manufactured, for example, by producing a carbon base material bycarrying out a first activation treatment to a carbon material obtainedby carbonization of a carbon compound, producing a formed body by addinga binder to the carbon base material, carbonizing the formed body, andfinally producing an active carbon electrode by carrying out a secondactivation treatment to the carbonized formed body.

Carbon fiber electrodes may be produced, for example, by using paper orcloth pre-form with high surface area carbon fibers.

In one specific example, multiwall carbon nanotubes (MWNT) arefabricated on any one of a variety of substrates by using chemical vapordeposition (CVD). The MWNT so fabricated are then useful in theelectrodes 33, 34. In one embodiment, low-pressure chemical vapordeposition (LPCVD) is used. The fabrication process may use a gasmixture of acetylene, argon, and hydrogen, and an iron catalystdeposited on the substrate using electron beam deposition and orsputtering deposition.

In some embodiments, material used to form the energy storage media 31may include material other than pure carbon. For example, variousformulations of materials for providing a binder may be included. Ingeneral, however, the energy storage media 31 is substantially formed ofcarbon, and is therefore referred to as a “carbonaceous material.”

In short, although formed predominantly of carbon, the energy storagemedia 31 may include any form of carbon, and any additives or impuritiesas deemed appropriate or acceptable, to provide for desiredfunctionality as the energy storage media 31.

The electrolyte 36 includes a pairing of a plurality of cations 39 andanions 41, and, in some embodiments, may include the solvent. Variouscombinations of each may be used. In the exemplary EDLC, the cation 39may include 1-(3-cyanopropyl)-3-methylimidazolium,1,2-dimethyl-3-propylimidazolium, 1,3-bis(3-cyanopropyl)imidazolium,1,3-diethoxyimidazolium, 1-butyl-1-methylpiperidinium,1-butyl-2,3-dimethylimidazolium, 1-butyl-3-methylpyrrolidinium,1-butyl-4-methylpyridinium, 1-butylpyridinium,1-decyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium,3-methyl-1-propylpyridinium, and combinations thereof as well as otherequivalents as deemed appropriate.

In the exemplary EDLC, the anion 41 may includebis(trifluoromethanesulfonate)imide,tris(trifluoromethanesulfonate)methide, dicyanamide, tetrafluoroborate,hexafluorophosphate, trifluoromethanesulfonate,bis(pentafluoroethanesulfonate)imide, thiocyanate,trifluoro(trifluoromethyl)borate, and combinations thereof as well asother equivalents as deemed appropriate.

The solvent may include acetonitrile, amides, benzonitrile,butyrolactone, cyclic ether, dibutyl carbonate, diethyl carbonate,diethylether, dimethoxyethane, dimethyl carbonate, dimethylformamide,dimethylsulfone, dioxane, dioxolane, ethyl formate, ethylene carbonate,ethylmethyl carbonate, lactone, linear ether, methyl formate, methylpropionate, methyltetrahydrofuran, nitrile, nitrobenzene, nitromethane,n-methylpyrrolidone, propylene carbonate, sulfolane, sulfone,tetrahydrofuran, tetramethylene sulfone, thiophene, ethylene glycol,diethylene glycol, triethylene glycol, polyethylene glycols, carbonicacid ester, γ-butyrolactone, nitrile, tricyanohexane, any combinationthereof or other material(s) that exhibit appropriate performancecharacteristics.

Once the EDLC is fabricated, it may be used in high temperatureapplications with little or no leakage current. The EDLC describedherein can operate efficiently over a wide temperature range, withleakage currents normalized over the volume of the device less than 1amp per liter (A/L) of volume of the device within the entire operatingvoltage and temperature range. One key to this performance is theassembly process itself, which produces a finished EDLC having amoisture concentration in the electrolyte of less than 500 parts permillion (ppm) over the weight and volume of the electrolyte and anamount of impurities less than 1,000 ppm.

In some embodiments, more specifically, the carbonaceous media making upeach of the electrodes 33, 34 is dried at elevated temperature in avacuum environment. The separator 35 is dried at elevated temperature ina vacuum environment. The electrolyte 36 is dried at elevatedtemperature in a vacuum environment. Once the electrodes 33, 34 theseparator 35, and electrolyte 36 are dried under vacuum, they arepackaged without a final seal or cap in an atmosphere with less than 50parts per million (ppm) of water. The uncapped EDLC is dried undervacuum over an elevated temperature range. Once this final drying iscomplete, the EDLC is sealed in an atmosphere with less than 50 ppm ofmoisture.

In addition, impurities in the electrolyte 36 are kept to a minimum. Forexample, in some embodiments, a total concentration of halide ions(chloride, bromide, fluoride, iodide), is kept to below 1,000 ppm. Atotal concentration of metallic species (e.g., Br, Cd, Co, Cr, Cu, Fe,K, Li, Mo, Na, Ni, Pb, Zn, including an at least one of an alloy and anoxide thereof), is kept to below 1,000 ppm. Further, impurities fromsolvents and precursors used in the synthesis process are kept below1,000 ppm and can include, for example, bromoethane, chloroethane,1-bromobutane, 1-chlorobutane, 1-methylimidazole, ethyl acetate,methylene chloride and so forth.

One example of a technique for purifying electrolyte is provided in areference entitled “The oxidation of alcohols in substituted imidazoliumionic liquids using ruthenium catalysts,” Farmer and Welton, The RoyalSociety of Chemistry, 2002, 4, 97-102.

Impurities can be measured using a variety of techniques, such as, forexample, Atomic Absorption Spectometry (AAS), Inductively CoupledPlasma-Mass Spectometry (ICPMS), or simplified solubilizing andelectrochemical electrochemical sensing trace heavy metal oxideparticulates based on a task specific ionic liquid.

AAS is a spectro-analytical procedure for the qualitative andquantitative determination of chemical elements employing the absorptionof optical radiation (light) by free atoms in the gaseous state. Thetechnique is used for determining the concentration of a particularelement (the analyte) in a sample to be analyzed. AAS can be used todetermine over 70 different elements in solution or directly in solidsamples.

ICPMS is a type of mass spectrometry that is highly sensitive andcapable of the determination of a range of metals and several non-metalsat concentrations below one part in 1012 (part per trillion). It isbased on coupling together an inductively coupled plasma as a method ofproducing ions (ionization) with a mass spectrometer as a method ofseparating and detecting the ions. ICP-MS is also capable of monitoringisotopic speciation for the ions of choice.

By reducing the moisture content in the EDLC to less than 500 part permillion (ppm) over the weight and volume of the electrolyte and theimpurities to less than 1,000 ppm, the EDLC can efficiently operate overa wide temperature range suited for use with the teachings herein, witha leakage current (I/L) that is less than 1,000 mAmp per Liter withinthat temperature and voltage range.

In one embodiment, leakage current (I/L) at a specific temperature ismeasured by holding the voltage of the EDLC constant at the ratedvoltage (i.e., the maximum rated operating voltage) for seventy five(75) hours. During this period, the temperature remains constant at thespecified temperature. At the end of the measurement interval, theleakage current of the EDLC is measured.

In some embodiments, a maximum voltage rating of the EDLC is 4 V at roomtemperature. An approach to ensure performance of the EDLC at elevatedtemperatures (for example, over 210 degrees Celsius), is to derate(i.e., to reduce) the voltage rating of the EDLC. For example, thevoltage rating may be adjusted down to about 0.5 V, such that extendeddurations of operation at higher temperature is achievable.

An energy storage 30 may be embodied in several different form factors(i.e., exhibit a certain appearance). Examples of potentially usefulform factors include, a cylindrical cell, an annular or ring-shapedcell, a flat prismatic cell or a stack of flat prismatic cellscomprising a box-like cell, and a flat prismatic cell that is shaped toaccommodate a particular geometry such as a curved space. A cylindricalform factor may be most useful in conjunction with a cylindrical tool ora tool mounted in a cylindrical form factor. An annular or ring-shapedform factor may be most useful in conjunction with a tool that isring-shaped or mounted in a ring-shaped form factor. A flat prismaticcell shaped to accommodate a particular geometry may be useful inconjunction with cylindrical, ring-shaped or other tools or toolsmounted in those form factors.

Examples of cylindrical tools or tools mounted in cylindrical formfactors include slickline or retrievable tools that are normallydisposed in the channel within a drilling apparatus. Examples of annularor ring-shaped tools or tools mounted in ring-shaped form factorsinclude collar-mounted tools disposed on the wall or collar of adrilling apparatus.

Some exemplary embodiments of the power system 16 with additional detailare now presented.

Generally, the power system 16 is designed and configured to operate atdepths and temperatures as may be encountered in the downholeenvironment. Generally, the power system 16 provides energy to at leastone of the survey components 15 and the downhole electronics 13, and mayprovide energy to any component in the logging instrument 10 oraccompanying the logging instrument 10 down the wellbore 1, and that hasa demand for energy that the power system 16 can provide.

First, note that the energy storage 30 may discharge an initial charge,and may also be recharged by a remote power source. Exemplary remotepower sources include power that is provided by at least one of thewireline 8, a rechargeable battery, a non-rechargeable battery, adownhole generator, and by a combination of thereof. In someembodiments, the downhole power source includes a battery that iscoupled to the energy storage 30, usually in close proximity so thebattery must also withstand the depths and temperatures presented to thelogging instrument 10. The downhole generator must also withstand thedepths and temperatures presented to the logging instrument 10.Generally, the generator uses a motive force, such as a flow of mud, orvibration to generate power.

Exemplary logging instruments 10 may include a variety of tools andcomponents used for geothermal resource development or oil and gasexploration, and may include logging while drilling (LWD) tools,measurement while drilling (MWD) tools, wireline tools, production toolsand so forth. Examples of these tools may include coring tools, shut-intools, NMR tools, EM telemetry tools, mud pulser telemetry tools,resistivity measuring tools, gamma sensing tools, pressure sensor tools,acoustic sensor tools, seismic tools, nuclear tools, pulsed neutrontools, formation sampling tools, induction tools, and so forth.

Further it is known that a variety of components may be included withinsuch tools. The components will consume power to provide desiredfunctionality. Non-limiting examples of these components includeelectronic circuitry, a transformer, an amplifier, a servo, a processor,data storage, machine executable instructions stored on or in machinereadable media (referred to as “software”), a pump, a motor, a sensor(such as a thermally tunable sensor, an optical sensor), a transducer,fiber optics, a light source, a scintillator, a pulser, a hydraulicactuator, an antenna, a single channel and/or a multi-channel analyzer,a radiation detector, an accelerometer, a magnetometer and the like.

In short, any equipment that may be deployed in support of and/or as apart of the logging instruments 10 and that consumes some electricalpower, or is driven by a component that consumes some electrical power,may benefit from use of the power system 16 and the accompanying energystorage 30.

Further, the logging instrument 10 may include or have an interface withany type of remote power source for charging that is deemed appropriateby a system user, designer and/or operator. Examples include low powerwirelines coupled to a remote power supply, or as deemed appropriate(for example, as may be dictated by system design). Other embodimentsmay call for coupling the power system 16 with on board powergeneration, such as a mud driven generator or alternator. Selecteddescriptions of various downhole tools are included below forperspective.

Coring tools are typically designed to extract samples of the rock orother formation material in the downhole environment. Examples arerotary coring tools, drill coring tools, sidewall coring tools, andothers. These tools typically include a motor that may demandinstantaneous amounts of power not easily available from standarddownhole power sources (batteries, generators, wirelines). The poweravailable to a coring tool downhole may impact the rate of coring and/orthe amount of coring material that may be extracted.

Shut-in tools may be used to isolate an area downhole in order toenhance the fidelity of measurements taken with other measurement toolsin that same isolated area. The shut-in tool stops or controls the flowof fluids that may otherwise flow during a downhole drilling operation.The shut-in tool typically includes a motor that demands a high powerpulse. The amount of power available to the shut-in tool determines thespeed at which the shut-in tool can stop the flow of fluid.

NMR (nuclear magnetic resonance) tools may be used to determine thehydrocarbon or other content in the rock or other formations surroundinga drilled hole. NMR tools typically require fast <1 sec, very highpower >1 kW power pulses to operate. The power available to an NMR toolmay impact the effectiveness of that tool to measure the salientfeatures of the formation.

EM (electromagnetic) telemetry tools may be used to transmit data fromthe subsurface application area to the surface using propagatingelectromagnetic radiation. EM telemetry tools may require high powerpulses to achieve useful transmission through the rock or otherformation at distances comparable to the said application depths. Thepower available to an EM telemetry tool may impact the range anddata-rate achievable for transmission to the surface.

Mud pulser telemetry tools may be used to transmit data from thesubsurface application area to the surface using propagating pressurepulses in the fluid (“mud”) that normally flows in a drilled hole. Mudpulser telemetry tools may require pulsed power to generate the neededpressure variations in the mud. The power available to a mud pulsertelemetry tool may impact the achievable signal fidelity.

Resistivity tools measure the electrical resistivity of the rock orother formation surrounding a drilled hole. Significantly, theresistivity of hybrocarbons differs measurably from that of typical rockand other materials that are found near drilled holes. Resistivity toolsmay measure the electrical resistivity with a number of methods. Onemethod is to apply a differential potential between two physicallyseparated points on the tool itself. The current that flows from onepoint to the other is then indicative of the resistivity of theformation surrounding the tool. The power available to the resistivitytool may impact the fidelity or the range of the achievable resistivitymeasurement.

Aspects of an embodiment of the power system 16 that includesrechargeable energy storage 30 are shown in FIG. 5. In this exemplaryembodiment, a first subsystem 52 includes current limiting electronicsand battery conditioning electronics. Due to the high power capabilityof the energy storage 30, the power system 16 may furnish bursts ofshort-duration current to the logging instrument 10. In the meantime, anexternal energy supply 51 (also referred to herein as a “source”) maysupply only relatively small but consistent current. Accordingly, onefunction of the first subsystem 52 is to limit current drawn from theexternal energy supply 51 during each burst. That is, during an intervalin which the power system 16 supplies large currents from the energystorage 30 to the logging instrument 10. This function may beparticularly critical when the external energy supply 51 is reliant onbattery technology. That is, typical battery technologies designed fordownhole operation have limited current handling capability and can failcatastrophically if too much current is demanded from them. Accordingly,the first subsystem 52 may be configured to limit the current drawn fromthe external energy supply 51. Further, as battery technologies mayrequire conditioning, for example, to de-passivate the batteryelectrodes prior to use, the first subsystem 52 may be configured toestablish the battery terminal conditions (current and voltage) neededto depassivate electrodes of the battery.

The first subsystem 52 and the second subsystem 53 may be controlled bya first subsystem controller 55 and a second subsystem controller 56,respectively. The first subsystem controller 55 and the second subsystemcontroller 56 may be combined to form at least a part of a controlcircuit 58 (which may also referred be to as a “controller” 58).

Chemical batteries, which may include several cells, may need to bedepassivated prior to use in order to reduce their effective outputimpedance so that operating currents do not cause an excessive decreasein the battery output voltage. Depassivation may be accomplished in oneof many ways. One exemplary method calls for drawing a constant loadcurrent from the cell for a short period of time. Exemplary currents mayrange from 10 mA to several amps per cell and exemplary depassivationtimes may range from a few seconds to several days. Current levels maybe changed or pulsed or otherwise during the depassivation procedure,for instance, a battery may be loaded at 4 mA per cell for three daysand then 150 mA per cell for thirty minutes. Depassivation should beperformed within a specified maximum time before actual use, for exampletwenty four hours.

The first subsystem 52 may be controlled in order to provide the neededcurrent draw from the battery for depassivation. The first subsystem 52may also incorporate measurement apparatus for determining the need fordepassivation. An exemplary implementation including components forautomatic depassivation is described below. A voltage and/or currentsensor (not shown) may be disposed between the external energy supply 51and the first subsystem 52. The first subsystem 52 may be controlled byway of the control circuit 58 or by a separate control circuit (notshown) to draw a specified current from the battery, for example 100 mA.If the resulting voltage presented by the external energy supply 51under the specified current load falls below a specified voltagethreshold (which may be determined a-priori to represent passivationconditions within the battery) within a specified time (for example 100ms), then the first subsystem 52 may determine that depassivation isrequired and otherwise not required. As example, 26 V is a commonthreshold for an eight cell moderate rate Li-thionyl chloride batterypack. If the first subsystem 52 determines that depassivation isrequired, it may be controlled to draw a specified current fordepassivation as exemplified above.

A battery is generally effectively de-passivated by drawing a specifieddepassivating load current and monitoring the battery voltage until itrises to a specified level. In one example, battery passivation isdetermined if a 28 V moderate rate battery voltage drops below 26 Vwhile drawing approximately 100 mA from the battery. If it does, thebattery is then normally de-passivated by drawing approximately 200 mAuntil the battery voltage rises above 26 V. Thus an automaticde-passivation may draw approximately 100 mA from the source and monitorthe voltage. If the voltage falls below 26 V for a 28 V battery, thesystem may then draw 200 mA from the battery and monitor the voltage.De-passivation may be halted, for example, once the power system 16measures a battery voltage above 26 V.

The depassivation current drawn from the battery may yield acorresponding current at the output terminals of the first subsystem 52which may be directed to the energy storage 30, in which case the energystorage 30 will be charged during depassivation. This method may beuseful when the energy storage 30 is in need of charging current. Thecurrent may also be directed to a dummy resistor or a zener diode or acombination thereof (not shown), or the like as an alternative. Thesealternatives may be useful when the voltage is already at or near therated voltage of the energy storage 30.

As shown in FIG. 6, an exemplary embodiment of the first subsystem 52includes a first switching device 61, and a second switching device 62as well as a filter inductor 63. The external energy supply 51 maycouple to the first subsystem 52 and to the energy storage 30 (forexample, a high temperature ultracapacitor). The action of the firstswitching device 61 and the second switching device 62 may be controlledto achieve current limiting and battery conditioning features describedabove. Specifically, the relative on-time of the first switching device61 and the second switching device 62 operating in a complimentaryfashion (duty ratio) may be used to adjust the conversion ratio and theflow of current. The exemplary first subsystem 52 shown in FIG. 6 may beuseful when voltage of the external energy supply 51 is larger in valuewhen compared to voltage of the energy storage 30. Current limiting orregulation may be achieved by way of a feedback control system (notshown).

An exemplary embodiment of the second subsystems 53 includes powerconverters either DC-DC or DC-AC depending on the tool requirements. Afunction of a second subsystem 53 may be to regulate the voltage orcurrent delivered to the logging instrument 10. Due to a capacitivenature of the energy storage 30, when implanted with an ultracapacitor,voltage of may decrease in an approximately linear fashion as charge iswithdrawn from the energy storage 30. A function of the second subsystem53 then may be to regulate the voltage or current delivered to thelogging instrument 10, despite the varying voltage presented by theenergy storage 30. Voltage limiting or regulation may be achieved by wayof a feedback control system (not shown).

As shown in FIG. 7, an exemplary embodiment of the second subsystem 53may include respective embodiments of the first switching device 61, thesecond switching device 62 as well as the filter inductor 63. Thelogging instrument 10 may couple to the second subsystem 53 and to theenergy storage 30. The action of the respective embodiments of the firstswitching device 61 the second switching device 62 may be controlled toachieve desired current or voltage regulation features described above.Specifically, the duty ratio of the relative on-time of the respectiveembodiments of the first switching device 61 and the second switchingdevice 62 may be used to adjust the conversion ratio and the flow ofcurrent or the presented voltage. The exemplary second subsystem 53shown in FIG. 7 may be useful when the voltage required is larger invalue when compared to the voltage of the energy storage 30. Voltagelimiting or regulation may be achieved by way of a feedback controlsystem (not shown).

As shown in FIG. 8, the first subsystem 52 and the second subsystems 53may be coupled together and to the energy storage 30 as well to providean embodiment of the power system 16. In this embodiment, the exemplarypower system 16 may be particularly advantageous when the terminalvoltage of the external energy supply 51 is either larger in value orsmaller in value when compared to the terminal voltage of the logginginstrument 10 as long as the terminal voltage of the energy storage 30is smaller in value than both.

In some embodiments, the power system 16 may be configured for lowstandby power consumption. This feature is advantageous in remote andharsh environments where power is scarce. Low standby power consumptionmay be achieved by incorporating low-power or micro-power gate drivecircuitry and control electronics in the control circuit 58.Additionally, an overall standby power consumption may be reducedsignificantly by incorporating a sleep state for the power system 16(discussed further below). In some embodiments, the low-standy powerstate may be characterized by a power down of circuitry to operation ofonly that circuitry that is required for power processing to deliverpower to the load or logging instrument 10 or for any applicationrequiring only a subset of circuitry. Sensing circuitry may beincorporated to determine when the logging instrument 10 is notdemanding power (active) or when the energy storage 30 is not in need ofrecharging current.

In some embodiments, a current sensor (not shown) may be disposed on aninterconnect between the first subsystem 52 and the energy storage 30.The current sensor may measure current draw from the energy storage 30.When the current draw falls below a certain threshold, a logic controlcircuit (such as logic included within control circuit 58) maypower-down a majority of the first subsystem controller 55. The controlcircuit 58, in its sleep state, may then intermittently, but in someinstances, on a time-scale much faster than the transient currentdemanded by the energy storage 30, awaken the first subsystem 52, andpoll the current sensor to determine if the energy storage 30 is in needof recharging.

As another example, a separate current sensor may be disposed on aninterconnect between the second subsystem 53 and the logging instrument10. This latter current sensor may be used to measure current draw bythe logging instrument 10. When that current draw falls below a certainthreshold, a logic control circuit that may be within the controlcircuit 58 may power-down a majority of the second subsystem controller56. The control circuit 58, in its sleep state, may then intermittently,but in some instances, on a time-scale much faster than the transientcurrent demanded by the logging instrument 10, awaken the secondsubsystem 53 and poll the current sensor to determine if the logginginstrument 10 is active.

As the energy storage 30 may exhibit a number of varying forms, theenergy storage 30 can be configured to integrate into the logginginstrument 10. For example, the logging instrument 10 may include anannular shaped energy storage 30, such as an annular shapedultracapacitor. In this embodiment, and by way of non-limiting example,the energy storage 30 may surround a mud channel or other equipment inthe drill string 11. The energy storage 30 may be segmented or otherwisedivided to accommodate form requirements and be coupled in series or inparallel as appropriate for the needs of the user.

In some embodiments, an automatic bypass is included in the power system16. That is, many applications may benefit from fail safe features. The“bypass” feature may be useful when any of the components of the powersystem 16, such as the first subsystem 52 the energy storage 30, thesecond subsystem 53 or the control circuit 58 or any other criticalcomponents fail to operate properly. In that case, it may be useful toconnect the external energy supply 51 directly to the logging instrument10 so that the external energy supply 51 may still provide utilitydespite the failed components. In some embodiments, the bypass featureautomatically determines a failed state of a critical component andsupplies an alternative current path from the external energy supply 51to the logging instrument 10. Because the bypass feature is useful uponthe occurrence of failed components and because of the inherentuncertainty therein, the bypass feature may, in some embodiments,provide for automatic operation. That is, the design may provide thatthe bypass feature is disabled by proper functioning of the respectivecritical components subject to the bypass. In some embodiments, such aswhere components are subject to high levels of shock and vibration, thebypass feature may be implemented with solid-state devices which may bemore robust in the environment than equivalent electromechanicalswitches, relays or the like.

One exemplary solid-state device that may be particularly useful inimplementing the solid-state automatic bypass feature is a semiconductordevice called a junction field effect transistor (JFET). A JFET is adevice having at least three terminals, normally called gate, drain andsource respectively that is “normally on,” meaning the device mayreasonably pass current unless a control voltage is imposed between thegate and the source of the JFET. An exemplary method for exploiting aJFET for automatic bypass is to connect the drain of the JFET to thehigh potential output terminal of the external energy supply 51 and thesource of the JFET to the high potential terminal of the logginginstrument 10. Additional functionality may be included in the controlcircuit 58 or in a separate control circuit (not shown). Thefunctionality may derive a gate to source drive voltage useful forturning off the JFET. That gate to source drive voltage may be derivedfrom a voltage or signal within the circuit that represents properfunctioning of all critical components. Many such signals or aggregatesof such signals may be derived from measurements by way of measurementapparatus for voltage and or current or otherwise. One indicative andexemplary signal that may be particularly useful for indicating properfunctioning of the power system 16 is terminal voltage of the energystorage 30. For instance, if the energy storage 30 falls below a usefulvoltage threshold, this may be construed as a failure of the firstsubsystem 52, thus indicating a loss of charging current from theexternal energy supply 51. This condition may also be taken construed asa failure of the second subsystem 53 indicating an excess discharging ofthe energy storage 30 to the logging instrument 10. Either of theseconditions may also indirectly represent a failure of the controlcircuit 58, and so this exemplary signal may in some cases be sufficientto determine proper functioning of the system components. That signalthen may be used to drive the gate to source voltage of the JFETdirectly or in effect directly, so that when it falls below a giventhreshold, the JFET will automatically revert to an undriven state, thatis a state that allows reasonable currents to flow from a drain of theJFET to source terminals of the JFET.

In further embodiments, it may be desired to include a current limitingfeature. Consider that a chemical battery or other power source mayrequire a current limit to prevent undervoltage of the batteryterminals, damage of the internal components of the battery, overheatingof the battery, excessively fast discharge, accelerated aging orpassivation of the battery, catastrophic failure of the battery and soon. A safety current limit may be implemented in the power system 16 inmany ways. Two exemplary methods for implementing the safety currentlimit described here may be used alone or in combination.

The first method exploits control circuitry, such as circuitry shown inFIGS. 5-8. For example, the control circuit 58 may derive a measurementof the power source current from the current sensor and a stateknowledge any voltage and current conversion ratio achieved by the powerconversion in the first subsystem 52. It may also derive a measurementof the power source current from the current sensor that may be disposedbetween the external energy supply 51 and the first subsystem 52.

The first subsystem 52 then may be controlled, for instance, byadjusting the relative on-time of the first switching device 61 and thesecond switching device 62 by operating in a complimentary fashion (dutyratio) to adjust and thereby limit the flow of current to apredetermined or otherwise determined value.

Referring now to FIG. 9, another embodiment of the power system 16 isshown. In the exemplary embodiment depicted in FIG. 9, the controller 45may be in electrical communication with an optional options module 99.Generally, the controller 45 communicates with and controls the energystorage 30 through a electronics management system (EMS) 91 circuit. Theelectronics management system (PEMS) 91 circuit may be in communicationwith (or, in some embodiments, include within the EMS 91), at least onesupervisor 92 which may include a respective electronics module 93. Theoptional options module 99 may also include a plurality of supervisor 92circuits, each of which may also include respective electronics modules93. Generally, the electronics management system (EMS) 91 is inelectrical communication with each of the supervisors 92 through aninternal bus 95.

As a matter of convention, the internal bus 95 may communicate energywithin the power system 16, as well as control signals and the like.Accordingly, the internal bus 95 may include a plurality of conductors,as well as non-conductive elements (such as fiber optic and the like).Thus, it should be considered that the representation of the internalbus 95 is intentionally simplistic, and is not to be considered limitingof internal communications within the power system 16.

Generally, power is provided to the power system 16 from at least oneexternal energy supply 51. Exemplary sources of external energy includeat least one battery, a remote power source (such as via wireline 8),and at least one generator. In some embodiments, the electronicsmanagement system (EMS) 91 receives energy from the external energysupply 51, and stores the energy in the energy storage 30. In general,the electronics management system (EMS) 91 is configured to managecharging and discharging of a variety of types of energy storage 30. Forexample, the electronics management system (EMS) 91 may be configured tomanage charging and discharging of ultracapacitors as well as at leastone type of battery. The electronics management system (EMS) 91 may drawon the energy storage 30 to provide a variety of energy forms. Forexample, pulses of power higher than those previously available down thewellbore 1 from a conventional external energy supply 51 may beprovided. Electrical properties for one exemplary embodiment areprovided in Table 1 below. Of course, these properties may be adjustedwith changes in design and/or scale, or other such parameters.

The at least one generator may be reliant on any one or more of avariety of technologies. Exemplary generators include generators thatmay be classified as a flow-driven generator (e.g., a turbine); adisplacement generator; a thermovoltaic generator; and the like.

In one embodiment, such as the embodiment of FIG. 9, electronicsincluded in the power system 16 are at least partially implemented usingdigital logic. For example, the electronics management system (EMS) 91circuit may include a digital circuit. One example of a digital circuitfor the EMS 91 is a microprocessor, model PIC18F4680, available fromMicrochip Technology Inc. of Chandler Ariz. The EMS 91 may communicateusing a digital protocol with a plurality of supervisors 92. Each of thesupervisors 92 may include a digital circuit. One example of a digitalcircuit for the supervisor 92 is a microprocessor, model PIC12F615,available from Microchip Technology Inc. of Chandler Ariz. Generally,each of the supervisors 92 receive data over a data bus 94. When aninstruction for a respective one of the supervisors 92 is received, therespective supervisor 92 (A-n) performs an assigned function. Forexample, supervisor 92A may receive an instruction from the EMS 91 todraw power from an internal battery. Accordingly, supervisor 92Acommands a respective electronics module 93 (in this case, electronicsmodule 93A), to draw on the internal battery that is contained in theenergy storage 30. In this example, the electronics module 93A includesa power converter and appropriate switching.

The options module 99 may be included in the controller 45 (as inaddition to the controller 45, physically separate therefrom).Generally, the options module 99 includes components that may bebeneficial for efficient energy management and/or provide users withuseful information. In some embodiments, each option of the optionsmodule 99 includes a respective supervisor 92 n and electronics module93 n. In these embodiments, each of the supervisors 92 may include adigital circuit. One example of a digital circuit for the supervisor 92is a microprocessor, model PIC12F615, available from MicrochipTechnology Inc. of Chandler Ariz. Generally, each of the supervisors 92receive data over the data bus 94 which may be shared with theelectronics management system (EMS) 91. When an instruction for arespective one of the supervisors 92 is received, the respectivesupervisor 92 (A-n) performs an assigned function. For example,supervisor 92D may receive a request from the EMS 91 for a temperaturereading. Accordingly, supervisor 92D commands a respective electronicsmodule 93 (in this case, power electronics module 93D), to ascertaintemperature from, for example, a resistive element. As another example,the EMS 91 may command supervisor 92C to store data. Accordingly, therespective supervisor 92C provides data, logging instructions and thelike to the respective electronics module 93C.

Each of the electronics modules 93 n may include devices as appropriateto execute the intended functionality. For example, at least one powerconverter may be included, as well as an integrated circuit, an IC chip,a microcontroller, a capacitor, resistor, inductor and other similarcomponents and assemblies of components.

The options module 99 may be fabricated and provided as a customized andmodular unit. That is, each options module 99 may be built with acertain functionality in mind while making use of a commoncommunications protocol.

The controller 45 may include an interface to an external communicationsbus 97. The external communications bus (ECB) 97 may be configured forcommunication with other tooling onboard or in communication with thelogging instrument 10. Exemplary other tooling includes a mud-pulser,other microcontrollers, digital and/or analog circuits and the like. TheECB 97 may use a proprietary protocol, or may use commercially availableprotocol(s). Using the ECB 97, a user may, for example, send at leastone command to the EMS 91 from the topside equipment 7. The at least onecommand may call for by way of example, changes in voltage, actuation ofany option, reading of stored data, and the like. The ECB 97 may alsoprovide periodic communications, such as communication of routine datalogging to the topside equipment 7.

Prior to discussing optional features in general, and in particularelectrical aspects thereof, it should be noted that the embodimentsprovided are not limiting and merely illustrative. For example,components and/or features may be moved about (i.e., related indifferent ways) within the power system 16, and some components and/orfeatures may be provided outside of the power system 16. Somecombinations of aspects of the various features described herein may berealized in other forms, or to present other functionality not discussedherein. Some aspects of the features described herein may be omitted,while other aspects of the features may be supplemented with technologynot presented herein. It should also be noted that the overview providedherein is presented as an abstraction of the techonologies andcapabilities of the power system 16, and is therefore merelyillustrative of aspects of the power system 16. That is, for example,the drawings and related discussions of embodiments of the power system16 as well as features, components and functions thereof, merely presentnon-limiting relationships and capabilities and are not intended to beconstrued as electrical diagrams and the like.

A variety of additional components and features may be included in theoptions module 99. Examples of additional components (which are notillustrated herein) include, without limitation, memory, at least oneaccelerometer, a magnetometer, a voltage measuring device, a gyroscope,a temperature sensor, a vibration sensing and measuring device, a shocksensing and measuring device, a flow sensing and measuring device, acurrent sensing and measuring device, at least one programmableinterface and circuit, any one or more of a plurality of customizedsolutions (some of which are introduced below) and the like. These andother components may provide for, among other things, data logging, datatransmission, measuring and/or controlling voltage, measuring and/orcontrolling current, as well as monitoring of temperature, shock,vibration, flow, orientation, trajectory, position and the like. In someembodiments, the additional components are provided in an additionalmodule (not shown), which may be coupled to the power system 16 via, forexample, a common bus. The module may be disposed, for example, betweenthe controller 45 and an interface.

In general, the power system 16 disclosed herein is adapted foroperation in the harsh environment encountered downhole. For example,the energy storage 30 and the power system 16 as a whole are, in someembodiments, adapted for operation in a temperature range from ambienttemperatures topside (although the power supply 16 may be configured foroperation in temperatures as low as about minus forty degrees Celsius)to about one hundred and seventy five degrees Celsius, or up to abouttwo hundred degrees Celsius. In some embodiments, the energy storage 30is adapted for operation at temperatures up to about two hundred andfifty degrees Celsius.

Some additional electrical functions and aspects of implementation ofthese functions are now presented. In general, and by way of exampleonly, these features may be implemented as subordinate to (i.e.,controlled by) a respective supervisor 92 and electronics module 93.Although these features are presented in the context of FIG. 9, thesefeatures are not limited to practice with the embodiment depictedtherein.

Exemplary additional functions that may be included in the power system16 include voltage simulation; state-of-charge monitoring; change-overcontrol; output voltage optimization; dual-mode control; temperatureprotection; sleep mode; memory logging; component bypass; and adaptivevoltage control, among others. It should be noted that some of theseadditional features are not mutually exclusive. That is, it isanticipated that at least one additional feature may be in use at anygiven time, and that implementation of that additional feature will notconflict with operation of other features. Some of these additionalaspects and functionality are now presented.

A first one of a variety of features that may be included in the powersystem 16 is that of voltage simulation. For example, a voltagesimulator may be included as an option within the options module 99 (orincorporated into the power system 16 in other ways, where no optionsmodule 99 is employed). In general, the voltage simulator simulates (or“mimics”) electrical properties of another types of energy supply.

Referring now to FIG. 10, there is shown an example of a simulator 80which includes a principal power system (PPS) 85. The principal powersystem 85 is depicted as being coupled to a source as well as a load.The source may be, for example, an energy storage 30 such as anultracapacitor. The load may be any equipment that presents a demand forenergy. Non-limiting examples of loads include pumps, motors and thelike, as well as electronics such as sensors, computing components andthe like. The load(s) may be disposed within other tooling, such as thelogging instrument 10.

In this exemplary embodiment of the principal power system 85, a powerconverter 81, a feedback controller 82 and a simulator map 84 areincluded. In general, the components used in the principal power system85 are known in the art of power control systems. Each of the powerconverter 81, the feedback control 82 and the simulator map 84 aredescribed in greater detail below. In general, the power converter 81receives power from the source and converts the power. The conversion isgoverned by the feedback controller 82, which in turn controls an outputsignal of the power converter 81 according to the simulator map 84.

FIG. 11 depicts some exemplary system configurations that include thebattery simulator 80. FIG. 11A represents an embodiment of a parallelconnection between an output of the battery simulator 80 another source.FIG. 11B represents an embodiment of a series connection between outputof the battery simulator 80 and another source. Optional powerconverters (the second power converter 81B and the third power converter81C) may be included. The optional power converters 81B, 81C may beincluded, for example, to harmonize output of the battery simulator 80and the additional source or the load. Other combinations are possible.For example, a plurality of battery simulators 80 could be coupled, manysecondary sources could be coupled, and a combination of parallel andseries configurations could be realized. In short, a variety ofconfigurations may be realized, and may generally include as manysources, loads, power converters and the like as needed.

Each of the power converters 81(A, B, C, . . . n) may generally be ofany topology. Non-limiting examples include converters commonly referredto as “buck,” “boost,” “buck-boost,” “flyback,” “forward,” “switchedcapacitor,” and other isolated versions of non-isolated converters(e.g., Cúk, buck-boost), as well as cascades of any such converters(e.g., buck+boost).

In some embodiments, each of the power converters 81 (A, B, C, . . . n)may support bi-directional power flow, especially when the source or atleast one additional source(s) are rechargeable.

An exemplary converter 81 is shown in FIG. 12. In this example, theconverter 81 is a bi-directional buck converter. This embodiment issuitable for, among other things, use as a power converter when theoutput voltage is required to be less than the input voltage.

Another exemplary converter 81 is shown in FIG. 13. In this example, theconverter 81 is a bi-directional boost converter. A further exemplaryconverter 81 is shown in FIG. 14. In this example, the converter 81 is amerged bi-directional buck-boost converter.

An exemplary embodiment of the feedback controller 82 is provided inFIG. 15. The components shown therein may be implemented in analog ordigital domains, or in a combination, as determined appropriate by adesigner, manufacturer or user. The feedback controller 82 may includeelements for monitoring and controlling various properties. For example,the feedback controller 82 may include components for frequencycompensation, pulse width modulation, deadtime protection, duty cyclelimiting, providing for a soft start (i.e., ramping voltage) and thelike.

The simulator map 84 may be implemented in a variety of ways. Forexample, in “analog” embodiments, the simulator map 84 may beimplemented through use of an actual replica of the simulated source(for example, with a smaller version of the simulated source). In someof these embodiments, the replica may be charged and discharged withassociated replica components.

In other embodiments, referred to as “digital” embodiments, amicrocontroller (coupled to memory, analog-to-digital converters,digital-to-analog converters and the like) senses a state of the sourceand maps (i.e., correlates) output conversion to known characteristics.More specifically, and by way of example, the microcontroller senses thestate-of-charge of the source via an analog to digital interface (forexample, through an analog to digital converter), evaluates the desired(expected) output from a battery according to a data table, curve, analgorithm, or other data set that is retrieved from memory, and thengoverns an output of the power converter 81 accordingly. The result isoutput from the microcontroller via a digital-to-analog interface (e.g.,a digital-to-analog converter). The analog output thus influences the“command” voltage for the feedback controller 82.

Separation between analog and digital may be realized at various placesin the principal power system 85. For example, the feedback controller82 may be fully implemented in a microcontroller, where the command isnot passed as an analog signal, but rather internally to themicrocontroller (or over a bus if, for example, a plurality ofmicrocontrollers is used). Generally, conversion from analog to digitaland back may be realized anywhere in the principal power system 85 thatis deemed appropriate by a system designer, manufacturer or user.

The commanded or regulated aspect of the power converter 81 (forexample, the output voltage) may generally include any property orcharacteristic as is practicable. For example, output current, outputvoltage, output power or a mix of output voltage, current and power maybe controlled. Other aspects include impedance, output resistance, andother such parameters. Generally, the output includes direct current(DC). However, in some embodiments, alternating current (AC) isprovided.

The sensed property of the source (the capacitor in the above examples)may generally consider any aspect deemed appropriate. For example, thesensed property(s) may include voltage, charge, impedance, current,temperature, and the like.

Referring now to FIG. 16, there are shown aspects of an exemplary stateof charge monitor 170. In FIG. 16, current from a battery is measured(I_(batt)) by way of a voltage measurement (V_(sense)) across an in-linesense resistor, R_(sense). The current may be deduced from the voltagemeasurement through knowledge of the resistance value, R_(sense) (inOhms). For example, by use of the relationship given in Eq. (1):

I _(batt) =V _(sense) /R _(sense)  (1).

The current may also be sensed by other techniques. For example, in someembodiments, the current may be sensed by way of a hall effect sensor orinductive sensor.

Generally, the power source (e.g., battery) is initially charged to afull state-of-charge. The monitor measures voltage on a periodic basis,such as once per millisecond. The measuring may be performed, forexample, at an analog-to-digital converter (ADC). Further, one may usethis method to update a state-of-charge variable in memory, rather thanstoring a full record of current over time. Thus, by calculatingstate-of-charge, there is no need to store a substantial amount of datafrom measurements. This may be particularly useful for transmittingstate-of-charge conditions from the monitor to a remote receiver, suchas from a downhole monitor to a topside receiver, or when memoryavailable downhole is in limited supply.

Another aspect of the power system 16 that may be included as anoptional feature is that of change-over control. In a variety ofembodiments, the energy storage 30 may include a plurality of energysources. When provided with the plurality of energy sources, the powersystem 16 may need to select particular ones of the energy sources toprovide power. For instance, in some cases, the power system 16 may drawupon two batteries. In one state, the power system 16 may draw from afirst one of the batteries. Once the first battery has reached aprescribed state (for instance, once the first battery has beensubstantially depleted), the power system 16 may draw power from anothersource, such as a second one of the batteries. Thus, a change-over ofsources is necessitated.

Note, however, that change-over is not necessarily as simple asswitching between sources. For example, the power system 16 may drawpower from another source alone or the power system 16 may draw powerfrom a combination sources including the first source and anothersource. In one example, the power system 16 monitors voltage presentedby one battery during discharge. The power system 16 will measure theloaded voltage, the open-circuit voltage, or a combination of the two.In some instances, the power system 16 will time average the batteryvoltage over periods that include both loaded and unloaded states. Thepower system 16 will use source voltage as an indication of remaininglife for the source. In some embodiments, the power system 16 will alsouse (in conjunction or separately) a state of charge monitor scheme thatmeasures the current supplied by the energy storage 30 and records theproduct of current and time and compare it to a-priori known value of afull state of charge capacity as an indication of remaining life andcontrol the changeover accordingly. The power system 16 may also use anyother method or any combination of methods deemed useful or appropriateby the designer to determine remaining life of a respective source or toindicate a needed changeover. The changeover may be implemented betweenbatteries, wirelines, generators, ultracapacitors, and any other form ofenergy source or combinations thereof as deemed appropriate or necessaryby the designer, user, manufacturer or other interested party.

Changeover can be implemented any number of ways. One example employsactive devices (for instance MOSFETs) in the current path for thevarious energy sources to be selected by the changeover controller. Forground-referenced logic-level input MOSFETs, the system PEMS 91 orrespective supervisor 92 may provide logic level control signals betweenthe gates and sources of the MOSFETs to activate them. For instance, toactivate one source and deactivate another, the changeover MOSFET forthe first source can be activated making a closed circuit connectionbetween the first source and the power system 16 and the changeoverMOSFET for the second source deactivated breaking a closed circuitconnection between the first source and the power system 16. Ifground-referenced MOSFETs are not suitable for any reason, MOSFETs maybe similarly placed in a high potential current path. In this case, thegate to source voltage of the MOSFET may require a level shift circuitto confine the gate to source voltage presented at the MOSFET terminalsto a safe range. In any case, the designer should consider the directionof inherent body diodes in active devices in order to effectively blockcurrent when a circuit is intended to be broken. Relays, analogswitches, fuses, resettable fuses, transistors, isolated gate drives orisolated active devices, and any number of devices may all be useful inimplementing changeover control. Changeover control may also beimplemented in a more linear fashion. For instance, the amount of powerdrawn from one source may be controlled over a continuum for instance,by controlling a resistance placed in the current path of that source.This may also be implemented with transistors. The control signal inthis case should resemble an analog rather than a digital or binarysignal.

A control signal commanding a change among sources (referred to as a“changeover command,” and by other similar terms) can be generatedwithin the EMS 91 or respective supervisor 92. The changeover commandmay be generated digitally, analogically, or with a mix of signals, andmay be generated outside of the EMS 91 or supervisor 92, such as by anytechnique deemed appropriate.

Change over may be manifested in any number of ways. For instance, thechange over may switch between batteries, it may switch from one batteryto a combination of two or several batteries or from one combination toanother combination, it may switch any number of times in a given timeperiod, it may switch repeatedly back to a state or between severalstates, in this way it may modulate between states to achieve aneffective time-average behavior, it may switch among any combination oftypes of energy sources for instance, wireline, generator, batteries,capacitors, flywheels or any other source deemed useful. The changeovercontrol may be informed by any information such as state of charge of anenergy source, voltage presented by a source, impedance presented by anenergy source, ambient temperature, vibration or other measurements,signals received from a remote location such as the surface in an oiland gas drilling application or any other source of information.

In FIG. 17, aspects of a topology for an exemplary change over controlunit 180 are shown.

Given the variable and extreme environmental conditions in which thepower system 16 will operate, a self adjusting voltage control featuremay be included to ensure operability of the power system 16.

A voltage adaptation circuit may be included in some cases to control amaximum voltage of the energy storage 30. Control may be according totemperature or some other external measurement (e.g., anotherenvironmental measurement), for example. More specifically, in someembodiments, the energy storage 30 will become increasingly unstablewith increasing temperature. Often, the instability is ameliorated bylimiting the voltage supported by the energy storage 30. For a hightemperature ultracapacitor, as temperature increases so may powercapability and energy capacity (as a result of decreasing effectiveseries resistance and increasing capacitance at elevated temperatures).Meanwhile both power capability and energy capacity increase with (thesquare of) the ultracapacitor voltage. Thus at elevated temperatures,voltages may be reduced while at least partially preserving powercapability and energy capacity as a result of decreasing effectiveseries resistance and increasing capacitance at those temperatures. Bydecreasing voltages at elevated temperatures, stability of the energystorage 30 may be improved at those elevated temperatures. This resultsin an attendant increase in a lifetime of the energy storage 30. Thisfurther permits extension of a maximum temperature rating of the energystorage 30 and therefore, in some embodiments where temperature ratingof the energy storage 30 is determinative, an extension of the maximumtemperature rating for the power system 16. As an example of voltageadaptation, management of string voltage according to temperature may beimplemented, for example, by providing a variable voltage set point forpower conversion, where the variable set point varies according tomeasurements of temperature. In one embodiment, temperature is measuredby a thermocouple coupled to the EMS 91, the PEMS 91 in turn sends avoltage set point command to a respective supervisor 92. Upon receipt ofthe voltage adjustment command, the respective supervisor 92 may controla power converter control circuit which adjusts the nominal or maximumvoltage output of the power converter control circuit.

Another exemplary feature of the power system 16 is that of multiplemode control. Multiple mode control (MMC) may be implemented to controlmultiple sets of aspects of the power system 16. For instance, in onemode, a user may wish to achieve a certain performance aspect which willprovide for reduced power losses internal to the energy storage 30 (inthis example, a battery), thereby extending the useable lifetime of thebattery. In this mode, for example, the power system 16 may beconfigured to provide a relatively low voltage. In another mode, theuser may wish to achieve a certain performance aspect leading toincreased output power to improve the efficiency of communication to aremote location. In this mode, for example, the power system 16 may beconfigured to provide a relatively higher voltage. In certain modes, thepower system 16 may be configured to provide a substantially highervoltage. Other performance aspects may include, by way of example,maximum output current or average output current, or any other aspectdeemed appropriate. Other modes may be desired. Any number of modes maybe made available.

Various methods of selecting modes may be implemented. For instance, auser may configure the power system 16 on the surface by programming thepower system 16 (such as by programming the electronics managementsystem (EMS) 91 over the external communications bus (ECB) 97. The usermay remotely configure the power system 16 by communicating over a datalink such as an EM link or a mud pulse link or a link created bycontrolling a flow of downhole fluid or any other link. The power system16 may be programmed to reconfigure itself in run-time. Distinct modesof operation may be achieved any number of ways. For instance, theelectronics management system (EMS) 91 may change a setpoint for theoutput voltage or output current of a feedback regulated power converterin run-time, thus changing the nominal output voltage or currentpresented by the converter. The electronics management system (EMS) 91may achieve this by applying, for example, analog or digital controlsignals to a respective supervisor 92, or by activating a device thatchanges control inputs, or by any other means deemed appropriate. In aconverter designed with digital feedback control, the change among modesmay be made digitally. In some cases, other circuit parameters may beeffectively changed when changing among modes. For instance, passivecomponents dictating stability of feedback loops may be changed when anominal output voltage is changed. Those components may be activelyswitched out and other components switched in as needed usingtransistors or other controlled switching devices. In the case ofdigital feedback control, stability of feedback loops may be maintainedby switching among different segments of code pre-programmed a digitalcontroller.

Another exemplary feature of the power system 16 is that of lowtemperature control. Low temperature control may be desired in certainenvironments. That is, performance of the an energy source (e.g., theexternal power supply 51) may deteriorate temporarily below certaintemperature ranges (a “low temperature threshold”, which may be anapproximate value, or range of values). Below the low temperaturethreshold, the energy source may be damaged if substantial power isdrawn therefrom. Consider, for instance, a downhole battery availablefrom Electrochem Solutions of Clarence, N.Y. (USA part number33-127-150MR SERIES: 4422 DD with a size rated for 200 mA of outputcurrent down to minus 40 degrees Celsius, the “low temperaturethreshold”). Below the low temperature threshold, this battery may onlybe capable of supplying about 1-50 mA without causing permanent celldamage.

Thus, the power system 16 may be configured with a low-temperaturecontrol circuit. The low-temperature control circuit is configured todetect temperatures in the low temperature range and then to limit thepower drawn from the energy source appropriately. Power drawn below thelow temperature threshold may be allotted to certain functions, such asto maintain operation of the power system 16 as well as a control systemfor detection of temperature and control of the power draw. Thus, insome embodiments, a power limit set-point is set above a power levelneeded to implement low temperature sensing and control. When an ambienttemperature for the environment rises above the low temperaturethreshold, the low-temperature control circuit may then progressivelyrestore power to selected components within the power system 16.

The power system 16 may be equipped to monitor temperature with avariety of devices. In some embodiments, the low-temperature controlcircuit is equipped with at least one of a thermocouple, a bandgapreference circuit and a resistance temperature detector (RTD). Othertechniques for measuring may be employed, and may include, for example,use of other components within the power system 16 that exhibittemperature dependence characteristics.

Power draw may be limited by simply disabling certain power systemcomponents, for instance power converters and sensor systems. Power drawmay also be limited by controlling the power draw of power systemcomponents for instance by regulating the output current or voltage froma power converter circuit. The system may be configured to resume normaloperation once temperatures rise above the low temperature range.

While discussed in terms of low-temperature protection, it should alsobe recognized that aspects of the foregoing may be useful in providinghigh-temperature protections as well. While temperature protectionprovides for reduced functionality of the power system 16, in someinstances, it is beneficial to induce an “over temperature shutdownmode” where the power system 16 is virtually shut down.

Another feature of the power system 16 is a “sleep mode.” A sleep modemay provide users with protection of the power system 16. Suchprotection may be beneficial for periods where the power system 16 isnot in use. For example, for periods of storage or transport where it isdesired to maintain the power system 16 connected to the energy storage30. Among other things, sleep mode will limit premature depletion of theenergy storage 30. More specifically, a certain level of “standby power”will normally be required to keep components of the power system 16active. If a given power system 16 is connected to the energy storage 30and left in storage or in transport for several weeks to months, it ispossible that the energy storage 30 would be substantially or completelydepleted. Consider the following example.

In one example, the energy storage 30 includes a battery pack that hasfour cells (for example, part number 33-127-150MR SERIES: 4422 availablefrom Electrochem Solutions of Clarence, N.Y.). The battery pack has acapacity of approximately 4 cells×3.67 V×29 Ah=425 Wh. A standby powerof 200 mW drawn by a power system connected to such a battery pack forfour weeks will deplete the battery pack approximately 67 Wh orapproximately 16% of the total capacity. If the power system 16 is sentinto storage with less than a full charge, or for an extended period oftime, the impact could be significant.

In some embodiments, the sleep mode is activated by detecting aneffective state of non-operation. Several methods may be employed. Inone example, the power system 16 is provided with at least one dustcap.A respective one of the dustcaps is equipped to electrically couple withthe power system 16. For example, the dustcap may include a jumper thatis configured to connect to pins in a connector of the power system 16.The EMS 91 will recognize when certain pins in the connector have beenconnected and command the sleep mode.

In one embodiment, detection of the connection calls for making the pins(in this example, two pins) that are connected by the dustcap correspondto pins on the EMS 91. The EMS 91 is configured to recognize a first oneof the pins as a digital output and the other pin as a digital input.The pin configured as a digital output may be set to a logic level forhigh, for instance, 5 V. Then, if 5 V is detected on the pin configuredas an input, the EMS 91 will interpret that as an indication of adustcap and thus a state of non-operation. Several combinations of pinconfigurations may be used to detect multiple states or to detectequivalent states caused by multiple distinct cases. Other methods ofdetecting a connection between pins may be used.

A dustcap (any type of cover, shield or packaging (all of which arereferred to as a “cover” for convenience) may be used) may also beconfigured to impose other conditions on the power system 16. Forinstance, the cover may present a certain electrical resistance acrosspins or any other type of impedance, it may present a voltage forinstance from a primary battery embedded in the dustcap, it may presentan ac signal or a digital signal created by a separate circuit or anyother means, it may present a nonlinear effect such as that provided bya diode. A connection to pins on a connector may require a rotatableconnector embedded in the cover as a dustcap is normally screwed onto apressure barrel. Thus a connection may mate with a receptacle and anouter portion of a dustcap may rotate about said connection. Aconnection may be implemented without a dustcap, it may be placedexplicitly to put the system in sleep mode, it may be connected to apower system at a connector other than the one present on the outside ofa pressure barrel. A sleep mode may be implemented by detection of nonoperation without an external connection to indicate non operation. Forinstance, a power system 16 may measure current delivered to a load andafter some time of delivered current less than a prescribed value,determine a state of non operation and control a power system to enter asleep mode. A power system may measure voltage on a capacitor or otherenergy storage element and determine that after some time of voltagedeviation less than a prescribed amount determine a state of nonoperation and control the power system 16 to enter the sleep mode. Othermethods may be employed as deemed appropriate or useful by the designer.

In some embodiments, the cover includes a component, such as at leastone of a resistor, a battery, a diode and the like. That is, the covermay include any component that will provide a unique electrical signalto the power system 16, when the cover is installed. When the powersystem 16 detects an associated unique electrical signal, the powersystem 16 will enter the sleep mode.

The sleep mode may consist of disabling or powering down unnecessarysystem components such as power converter or sensor components requiredonly during operation. It may also change a system parameter such asoutput voltage temporarily to for instance reduce standby power consumedin the self discharge of energy storage or in other resistive elements.

Another feature that may be included in embodiments of the power supply16 enables data logging. That is, a memory logging circuit (i.e.,module) may be included in the power system 16. The memory loggingcircuit may include memory and an interface to receive event data. Thisdata may be useful for controlling system operation, sending systemstatus to a remote location, or debugging or assessment of the systemafter operation among other uses. Some examples of data that the systemmay record include battery voltages, battery currents, battery states ofcharge, temperature, vibration, shock events, logic level signalsindicating measured fluid flow, mud pulse actuation for an MWD mudpulser, battery changeover state, etc. The memory logging circuit mayfurther include processing capabilities (i.e., a memory loggingprocessor) as appropriate to receive and store the event data. Thememory logging processor may also retrieve event data from memory andcommunicate the event data for transmission to the user.

Generally, a rate of data sampling and data parameterization is to becarefully selected to ensure storing of a useful amount of information.That is, memory rated for operating at high temperatures is generallyless dense than memory rated for operating at lower temperatures.Accordingly, in some embodiments, data sampling and logging areperformed at rates that are commensurate with a rate of change. In someembodiments, sampled data is parameterized (i.e., used to update fittingvariable representing an aggregate parameter, such as a state of chargeor damage fraction). Some examples are provided. For instance, in someembodiments, slow changing signals are only sampled every few minutes.Vibration data is parameterized as a time-average of rms accelerationmeasured from an accelerometer over a specified time window (e.g. 10seconds). Battery state of charge is stored as a single data point thatis updated as battery current is measured over time (as opposed tokeeping a full record of battery current). Shock events are time-stampedand recorded as single events during which acceleration exceeded aspecified limit (e.g. 35 Gs). A combination of volatile and non-volatilememory may also mitigate the scarcity of high density memory operatingat high temperatures. That is, non-volatile memory (memory that retainsits state despite loss of power), is generally less dense but will notlose its data in the event of a fault in an energy source, thus it isbeneficial to retain data in non-volatile memory especially in hostileenvironment applications. Meanwhile volatile memory is generally moredense, but will not necessarily retain its data in the event of a faultin an energy source. In some embodiments, a compromise design is usedthat generally stores all data in volatile memory, so that a longerrecord may be had, while periodically archiving data to non-volatilememory.

By way of example, in the compromise design for memory management, theuser may have access to a recent 100 hours or so of data record in theevent of a fault in an energy source. The most recent data since thelatest archive may be lost. This effect may be mitigated by archivingmore often. However, non-volatile memory is generally rated for aspecified number of write cycles. Thus, a tradeoff may be made. Forexample, if the system needs to last 2,000 hours and a ROM (non-volatilememory) is rated for 10,000 write cycles, we might archive data every2,000 hours/10,000 cycles×60 minutes=12 minutes. Thus, the user may losein a worst case 12 minutes of the most recent data, and statisticallywill expect to lose 6 minutes of the most recent data. This effect maybe further mitigated by adding several ROMs to the power system 16 sothat one ROM may be written for a number of time (for example, 10,000times) and then regarded to be at end of life, then a second ROM may bewritten to 10,000 times and so on, such that more than 10,000 writecycles are available to the power system 16 and archiving can take placemore frequently. Meanwhile, if there is no fault in an energy source, afull record of data may be available in the RAM (volatile memory).Accordingly, it should be recognized that a variety of memory managementschemes may be employed.

An exemplary memory component is a one megabit high temperature ROM(EEPROM) is available from TT semiconductor Anaheim, Calif. USA (partnumber TT28HT010). This exemplary component is rated for operation up toabout 200 degrees Celsius. Another example is available from the samemanufacturer and is a 16 Mbyte RAM (SRAM), (part number TTS2MWV8) israted for operation up to about 220 degrees Celsius.

As discussed above, one of the features that may be included inembodiments of the power system 16 is the bypass feature. Someadditional aspects of the bypass feature are now discussed.

In some embodiments, the bypass feature is implemented with at least oneof a separate and a redundant power converter (referred to as a “bypassconverter”). In that case, it may be desirable to block current flowinto or out of the output of components that are bypassed. Thus, aswitch network may be included in the power system 16. In someembodiments, the switch network includes a diode with the output of afirst converter so that the diode will block current flow appropriately.In some embodiments, the diode will not be appropriate (such as wherethe diode causes excessive power loss or blocking of current flow in abi-directional design), so a MOSFET or other active device may beemployed. In embodiments making use of at least one MOSFET or at leastone other type of transistor as the switch, the switch device is coupledto an appropriate gate or base or other drive circuit to safely activatethe switch device. In the case of a MOSFET, the inherent body diodeshould be considered to block current flow in both directions. A seriesdiode opposing the direction of the body diode may be employed to blockcurrent in both directions. Combinations of MOSFETS may also beemployed. Combinations of MOSFETs and diodes may be employed as well. Insome topologies, functionality of the switch network may be inherent tothe circuit and so an additional switch network is not needed. Forinstance, in a boost converter having an asynchronous high side switch(a diode), the converter will only conduct substantial current from thesource to the load in the high potential path. Thus, if thefunctionality required of the switch network is that current cannot flowfrom the load to the source in the high potential path, then noadditional switch network is needed.

The bypass feature may be particularly useful when a component of thepower system 16 is not in a state that is suitable for providing power.For instance, the bypass feature may be useful when a subsystem or theenergy storage 30 has failed. The bypass feature may also be useful whenthe energy storage is in a low state of charge or when the power system16 has entered a mode of operation that prohibits it from utilizing theenergy storage 30 or another system component. Other uses of the bypassfeature may present as the designer finds them appropriate.

Some embodiments of a bypass controller are depicted in FIG. 18. InFIGS. 18A, 18B and 18C, a bypass controller 190 is depicted in variousrelations to components of the power system 16.

Yest another feature that may be included in the power system 16 is anoptimization module. In embodiments include an optimization feature, thepower system 16 may adjust operation to optimize an overall performanceaspect. This adjustment may occur in run time. For instance, the powersystem 16 may target an optimized overall system energy efficiency. Thepower system 16 may be configured to consider the sum of all powerlosses. For example, the power system 16 may be configured to monitorlosses in the load as the losses vary with load voltage, losses in theenergy source as they vary with rms current levels, standby power lossesin keeping a power converter controller active, leakage power losses inthe energy source and the like. Using this information, the optimizationfeature is tasked with reducing overall power loss.

In order to provide for optimization, the optimization module may employany one or more of a variety of techniques. For example, theoptimization module may compute optimal parameters such as those thatadjust rms current draw from the energy source, relative on-time of apower converter control circuit, output voltage presented to a load,voltage presented to the energy storage 30 and the like. Theoptimization circuit may also employ a “perturb and observe” method, byperturbing one parameter and re-measuring system efficiency, thenattempting to adjust the perturbations in a direction that decreasestotal power loss. An optimum or a local optimum may be identified whenperturbations in either direction result in an increase in measuredpower loss. Avoidance of local optima that are substantially suboptimalin a global sense may be aided by combining the perturb and observeseeking algorithm with a first computation. The first computation shouldlocate the set of system parameters relatively near to the global(system) optimum. It may attempt to do so by first considering anestimated sum of all losses in the power system 16. The sum may includeloss terms derived from run-time measurements, loss terms derived froma-priori or pre-programmed values, loss terms derived from computation,and loss terms derived from a combination of the above. The firstcomputation may attempt to locate a global optimum by computing the sumfor various sets of system parameters and choosing the set of systemparameters yielding the minimum computed power loss among all sets ofsystem parameters. The first computation may also attempt to compute aderivative of the sum to locate a set of local optima and then backsubstitute the system parameters into the original sum expression toarrive at a set of local optima in order to choose the global optimum.

Further, the optimization module may adjust optimization in run-time assystem parameters change, for instance as time-average load current orpower changes, as the energy storage 30 ages, as temperature increasesand leakage current of the energy storage 30 increases, etc. The powersystem 16 may be aided to that end by the ability to measure voltagesand currents for instance, source voltages and currents, load voltagesand currents, its own standby currents, currents flowing into the energystorage 30, etc. The optimization module may further combinemeasurements to determine other aspects such as battery internalresistance as it may be derived from two distinct pairs of measurementsof battery voltage and current. An internal resistance of the energysource may be taken as an input to an optimization.

In some cases, an optimized output voltage leads to higher efficiency(less loss) in some embodiments of the power system 16. Consider thefollowing example. In an MWD mud pulser system, a lower voltage mayproduce sufficient motor actuation with less dissipation. Normally, ahigh voltage battery is needed to drive an MWD pulser becauseinstantaneous voltage drops during pulses of output power and the loweroperating voltage limit of the MWD system must be accounted for whenchoosing the battery voltage. That is, some head room must be includedin the battery voltage to account for droops resulting from its internalresistance. Otherwise, those droops may breach a lower limit voltagethreshold that could cause shutdown of the power system 16 of otherunwanted behavior. However, such a battery voltage may not be optimalfor mud pulser efficiency and thus battery life. Accordingly, the powersystem 16 may be configured to buffer the battery voltage and presentpower to the MWD pulser. In this case, the power system 16 may provide asubstantially more fixed output voltage compared to a battery as aresult of feedback regulation and or low output series resistance of theenergy storage 30, a power converter or both. Thus the consideration forhead room that is typical with a battery-only design is significantlyrelaxed. A lower voltage may be presented to the MWD pulser withoutconcern for breaching a lower limit voltage threshold. Meanwhile, theMWD pulser operating under a lower voltage may be more efficient.Ultimately, this efficiency leads to longer life of a battery in theenergy storage 30 because there is less battery energy wasted ininefficiency. In one example, an MWD mud pulser may accept voltages from15 to 29 V. A 7 or 8-cell battery is normally chosen to achieve voltagesof approximately 25 to 28 V. During operation and as the batterydegrades over its lifetime leading to an increase internal resistance,instantaneous voltages may drop from the open-circuit battery voltagedown to 20 V or less during pulsed power delivery to the MWD pulser.Once the battery voltage reaches a lower threshold measured in either aninstantaneous fashion or a time-averaged fashion or otherwise, a systemmay cease to function properly or may intentionally shut down. Meanwhilean MWD pulse driven from a 28 V battery may consume approximately 15 Jof energy. Instead, the power system 16 may be coupled to the batteryand the MWD pulser. The power system 16 may provide a relatively fixed20 V to the MWD pulser over the life of the battery. Meanwhile an MWDpulse driven by a 20 V power system output may consume approximately 11J of energy representing an approximately 26% energy savings. An exampleof an MWD pulser system that exhibits this behavior is a Benchtree MWDmotor drive mud pulser (part number 900370) available from Benchtree,Georgetown Tex. USA.

A system health monitor may be provided as yet another feature. A systemhealth may be derived from measurements and records of temperature,vibration and shock and corresponding durations. A damage fraction maybe pre-defined based on empirical and statistical tests.

The power supply 16 may include redundant features in the architecturethereof. For instance, additional power electronics circuits may beincluded. Additional capacity in the energy storage 30 may be included.The power system 16 may be configured to deactivate a component upondetection of a fault in that component and to then activate a redundantcomponent. A circuit may be deactivated by at least one of disablingcontrol circuits, breaking power connections to it, and disconnecting itfrom inputs and outputs using active devices such as transistors orrelays. Energy storage 30 may likewise be deactivated by disconnectingit from inputs and outputs using active devices.

A fault may by identified in any number of ways and will depend on thetype of fault to be identified and the type of component that may havefailed. For instance a power converter fault may be indicated by aninability of the converter to maintain an output voltage within typicallimits for longer than a specified amount of time so long as the outputpower draw is within typical limits. An ultracapacitor fault may beidentified as a low or nearly zero voltage despite normal voltagespresent on series connected ultracapacitors. This may specificallyindicate a short circuit type fault. Fault detection may be aided byemploying voltage measurement devices such as resistor dividers coupledto analog to digital converters further coupled to the PEMS 91 or othertype of controller. Faults and damage fractions may be recorded inmemory (such as by techniques provided herein) and, among other things,reported to the user.

Having thus described aspects of electrical performance of the powersystem 16, some additional aspects are now provided. In general, theseadditional aspects relate to construction and fabrication of the powersystem 16.

Referring now to FIGS. 19 through 24, further aspects of the powersystem 16 are shown. In FIG. 19, an embodiment of the power system 16suited for incorporation into the logging instrument 10 is shown. Inthis example, the power system 16 has a form factor that simplifiesincorporation into a drill string 11 or a wireline 8. More specifically,in this example, the power system 16 is provided as an elongated,cylindrical container 47 and includes an interface 46 (in thisembodiment) at each end. Within the container 47 is a plurality ofultracapacitors as the energy storage 30. Charging and discharging ofthe energy storage 30 may be controlled by controller 45, whichcommunicates power through the interface 46. FIG. 20 provides anexploded view of the embodiment of the power system 16 depicted in FIG.19.

The power system 16 and the components thereof may be assembled in a“modular” fashion. That is, modular architecture of the power system 16provides for customizing each power system 16 and providing moreexpedient fabrication. Aspects of modular construction will become moreapparent when considering aspects introduced below.

Referring to FIG. 21, there is shown an embodiment of the controller 45.In this example, the controller 45 exhibits a form factor suited fordisposition within the cylindrical container 47. Accordingly, thecontroller 45 may include at least one insulator 65. In this example,the controller 45 is generally bounded by an insulator 65 disposed ateach end, and further includes an intermediate insulator 65. Each of theinsulators 65 generally provides physical separation of the controller45 from other portions of the power system 16, and may be used forincorporation of other features such as an anchor for a plurality ofstandoff supports 64. The insulators 65 may be fabricated from anysuitably insulative material, such as polytetrafluoroethylene (PTFE) oran equivalent. The insulators 65 may be tightly fit within the container47, such that intermediate components are physically held into placewithin the container 47. Generally, each of the insulators 65 mayinclude at least one physical feature, such as at least one notch orhole, to provide at least one access-way. The at least one access-waymay provide access for, by way of example, passage of wires,encapsulation and the like.

The standoff supports 64 collectively provide for mounting andseparation of a plurality of circuits 62. The circuits 62 may includecomponents disposed, for example, on a circuit board. The circuits 62may include components such as, for example, a plurality of capacitors.In some embodiments, at least one inductor 63 is included. In someembodiments, a plurality of inductors 66 is included. The plurality ofinductors 63 may be wound with a single conductor. The single conductormay be used in some embodiments, to provide the plurality of inductors63 with robust physical strength in harsh environments (such as whereexcessive vibration will be encountered).

Generally, the standoff supports 64 provide a rigid support maintainingspacing between each circuit 62. Each of the standoff supports 64 may befabricated from materials as appropriate, such as metallic materialsand/or insulative materials, such as forms of polymers.

In the illustration of FIG. 21, each of the circuit boards is generallydisposed perpendicular to the Z-axis when in service. Thus, each of thecircuits 62 generally absorbs and distributes stress evenly across thecircuit 62, and experiences minimal perturbation from any mechanicalstress. In short, each of the circuits 62 may include a design thatprovides for minimizing at least one of stress and strain experienced(i.e., axial forces are compressive rather than sheer). Generally, eachof the circuits 62 may include features, such as at least one notch orhole, to provide at least one access-way. The at least one access-waymay provide access for, by way of example, passage of wires,encapsulation and the like. A form factor (i.e., a physical appearance)of each circuit 62 may be adapted in any way desired to provide for suchaccommodations. For example, instead of a circular circuit board, thecircuit board may have two to many sides (n-gonal).

At least two of the storage cells 42 may include at least one insulator65 disposed there-between. Each one of the storage cells 42 may includeother forms of insulative materials, such as, for example, a polyimidefilm such as KAPTON, provided by Dupont Chemical Corp. of Delaware.Generally, KAPTON is used as it remains stable in a wide range oftemperatures. Each of the storage cells 42 may be wrapped in theinsulative film, which among other things, may be used to provide forprevention of electrical shorting.

Once the various modular components have been assembled (i.e.,interconnected), these are installed within the container 47. Forexample, the assembly may be inserted into the container 47. In order toensure a mechanically robust power system 16, as well as for preventionof electrical interference and the like, in some embodiments,encapsulant may be poured into the container 47. Generally, theencapsulant fills all void spaces within the container 47.

Embodiments of the encapsulant may include, for example, SYLGARD 170(available from Dow Corning of Midland Mich.), which is a fast curesilicone elastomer that exhibits a low viscosity prior to curing, adielectric constant at 100 kHz of 2.9, a dielectric strength of 530volts per mil v/mil, and a dissipation factor at 100 Hz of 0.005, and atemperature range of about minus forty five degrees Celsius to about twohundred degrees Celsius. Other encapsulants may be used. An encapsulantmay be selected, for example, according to electrical properties,temperature range, viscosity, hardness, and the like.

In general, each of the circuits 62 may represent at least one valueadded feature for a user (such as some of the foregoing features,including for example those features described as options in the optionsmodule 99), and may be included in the power system 16 as needed. As amatter of convention, a “value added feature” may be considered as afeature that is useful in controlling the power system 16. For example,a value added feature may include capabilities for data logging,telemetry, a state-of-charge monitor, battery change over control, powerconversion, a digital supervisor, at least one interface (such as aserial interface), a health monitor and the like.

Accordingly, there may be a common electrical bus for connecting of thevarious circuits 62. The electrical bus may include wired assemblies(such as a bus that includes a plurality of conductors soldered orotherwise connected between the circuits 62). The electrical bus mayinclude other technologies as well.

That is, the electrical bus may include other forms of connections inplace of or in addition to wired assembly. For example, the bus mayinclude at least one bus connector. The bus connector may include, forexample, a mateable male component and a mateable female component,where each component may be attached to a respective one of the circuits62. In these embodiments, the bus connector may additionally provide forsome degree of physical support within the controller 45. The busconnector may include one to many conductors, and may be selected for,among other things, acceptable temperature range of operation,mechanical properties (such as rigidity). Each of the mateable malecomponent and the mateable female component may be pre-fabricated onto arespective one of the circuits 62, or later added to the respectivecircuit 62 as the various circuits to be used in the power system 16 areidentified. A variety of bus connectors may be used. See, for example,FIG. 22.

In FIG. 22, a simplified view of a bus connector 70 is shown. In thisexample, a female component 71 includes a latching device for latchingwith a male component 72. When assembled, the female component 71 andthe male component 72 provide for electrical communication as well asstructural support between the two circuits 62. Additional busconnectors 70 may be used. For example, another bus connector 70 may bedisposed at an opposite side of the circuits 62 to provide for increasedstructural strength.

The bus connector 70 may be surface mounted, may be mounted in at leastone through-hole, mounted in series (or parallel), or in any mannerdeemed appropriate. In some embodiments, the bus connector 70 is adaptedfor incorporation of an intermediate device, such as a ribbon cable (notshown). The ribbon cable may include, for example, polyimide flexiblematerial suited for high temperature operation.

As depicted in FIG. 20, the energy storage 30 may include a plurality ofstorage cells 42. The storage cells 42 may be electrically coupled in avariety of configurations. Reference may be had to FIGS. 23 and 24 formore detail on the construction of the energy storage 30 from aplurality of singular storage cells 42.

Referring to FIG. 23, the storage cell 42 includes a cathode 83 disposedat a top. The housing 37 of the storage cell 42 provides an anode 87.The cathode 83 and the anode 87 are electrically separated by anintegrated insulator 63. For example, the cathode 83 may be an electrodeincluded in a glass-to-metal seal incorporated into the housing 37. Inorder to protect the storage cell 42 from unwanted electricalinterference, the housing 37 may be wrapped in a wrapper 74 of aninsulative material, such as a film of the KAPTON discussed above. TheKAPTON may include a high temperature adhesive disposed thereon toensure adherence to the housing 37. Generally, in some embodiments, thewrapper 74 provides electrical insulation over the entire housing 37,with exceptions for the cathode 83 and a bottom surface of the housing37.

In some embodiments, the cathode 83 is fabricated from stainless steel,however, this is not a requirement.

In some embodiments, a washer 75 may be disposed over the wrapper 74.The washer 75 may be fabricated from similar materials as the wrapper 74(e.g., from a KAPTON film). In general, the washer 75 is dimensioned soas to fit snugly around the cathode 83 and to provide coverage of theentire top of the housing 37. Subsequent to placement of the washer 75,a tab may be affixed to the cathode 83.

Among other things, the washer 75 provides for additional electricalinsulation in the energy storage 30. Of course, while the washer 75 maybe placed about the cathode 83 (as shown and described), the washer 75may be placed about the anode 87 (for example, consider the assembly ofFIG. 23 with reversed polarity). Accordingly, the washer 75 may beplaced about at least one electrode (i.e., anode and/or cathode) asdeemed appropriate.

Referring now to FIGS. 24A and 24B, collectively referred to herein asFIG. 24, aspects of assembly of the energy storage 30 are shown. In FIG.24A, two storage cells 42 are placed side-by-side. A tab 88 is affixedto the cathode 83 of a first one of the energy storage cells 42, andalso affixed to the bottom surface of a second one of the energy storagecells 42. Once the tab 88 is suitably affixed (such as by laser, spot,tig, resistance, ultrasonic or other form of welding) the second one ofthe energy storage cells is rotated into an upright position, asdepicted in FIG. 24B.

In one embodiment, nickel is used to fabricate the tab 88. However,material used for the tab 88 may include any material deemed to exhibitsuitable properties (such as weldability, strength, conductivity and thelike).

Series connection of the storage cells 12 is one exemplary aspect of theenergy storage 30. In other embodiments, the energy storage 30 mayinclude storage cells 12 that are connected in parallel, or in somecombination of series and parallel.

When a plurality of storage cells 42 are assembled into a stack (i.e.,in series), as shown in FIG. 24B, a gap 86 is realized between each ofthe storage cells 42. An insert (shown in FIG. 20), may be disposedbetween each of the storage cells 42. In some embodiments, the insert 49is fabricated from a high-temperature insulative material, such as, forexample, polytetrafluoroethylene (PTFE). The insert 49 provides for,among other things, distribution of mechanical forces, and ensureselectrical separation of respective anodes 87 during operation.

Once the energy storage 30 is assembled in a final form, then the powersystem 16 may be “potted.” That is, once the power system 16 is insertedinto the container 47, the container 47 may be filled with encapsulant.Among other things, the encapsulant provides for damping of mechanicalshock as well as protection from electrical and environmentalinterferences within the power system 16. In one embodiment, the powersystem 16 was filled with SYLGARD® 170 silicone elastomer (availablefrom Dow Corning of Midland, Mich.) as the encapsulant. The encapsulantmay also provide for thermal conduction so as to dissipate excess heataway from, for instance, a circuit component.

Having thus described aspects of the power system 16, it should berecognized that a variety of embodiments may be realized. For example,the power system 16 may include circuits that provide a state of chargemonitor for monitoring charge in at least one of the storage cells 42 ora battery coupled to the power system 16 (not shown); the power system16 may include control circuitry for drawing power from one or more ofseveral battery packs arranged, for example, in a redundantconfiguration; the power system 16 may provide for a motor drive; mayinclude various sensors, such as pressure, temperature and vibration(which may provide output to control circuitry for controlling the powersystem 16 as appropriate); and the like.

In general, the power system 16 disclosed herein is adapted foroperation in the harsh environment encountered downhole. For example,the energy storage 30 and the power system 16 as a whole are, in someembodiments, adapted for operation in a temperature range from ambienttemperatures up to about one hundred and seventy five degrees Celsius.

Some exemplary off-the-shelf components and techniques that may be usedin the power system 16 include: (1) bare die silicon andsilicon-on-insulator active devices, (2) silicon carbide active powerdevices, (3) high temperature rated and low temperature coefficientceramic passives (COG or NPO dielectrics), and (4) high temperaturemagnetic passives. AN (aluminum nitride) ceramics may be used as acircuit substrate material for excellent thermal stability and thermalconductivity. Circuit interconnects may be formed of oxidation resistantAu traces. Bonding strategies may employ flip chip or Au or Al wirebonding for bare die active components using, for instance, AuGe hightemperature solder. In some embodiments, wire bonding is expected to beadvantageous over flip chip bonding due to the added mechanicalcompliance, especially in the presence of thermal expansion and shockand vibration.

High temperature circuit techniques may be employed, for example, toensure stability of feedback regulation circuits despite very widetemperature swings as passive circuit components used for frequencycompensation may vary in value. Low or essentially zero temperaturecoefficient circuit designs can be achieved by coupling negativetemperature coefficient resistors with conventional resistors, byclosely matching active devices and by relying on ratiometric (relative)rather than absolute sensing and control. As an example, bandgap derivedvoltage references can be employed to cancel the effect of very widetemperature variations on set points in feedback regulation circuits.Temperature coefficient strategic component selections mitigate theseproblems as well, for instance CGO or NPO dielectric ceramic capacitorshave a relatively flat response to temperature across this range. Activedevice performance variations can be significantly mitigated by use ofsilicon-on-insulator (SOI) and silicon carbide (SiC) technology widelyavailable in both hermetic and bare die form.

Other high temperature materials, components and architectures as areknown in the art may be employed to provide for operability at aspecified (high) temperature.

Silicon-on-insulator (SOI), Silicon Carbide (SiC), bare die components,ceramic PCB's, low temperature coefficient passives and hightemperature, hi-rel solders will all be sourced to complete theelectronic systems. A non-exhaustive list of commercial suppliers foreach of the above components is included in Table I below.

TABLE I Exemplary High-Temperature Components Manufacturers ComponentVendor SiC Bare Die Transistors Micross Components, Los Angeles, CA USASiC Bare Die Schottky Micross Components, CA USA Diodes Si and SOI BareDie linear Minco Technology Labs LLC, Austin, TX and digital circuitsUSA Ceramic Surface Mount Digikey, Minneapolis, MN USA CGO, NPOcapacitors Ceramic Surface Mount Digikey, Minneapolis, MN USA ResistorsBare Die Magnetics Minco Technology Labs LLC, Austin, TX USA CeramicPrinted Circuit Complete Hermetics, Santa Ana, CA USA Board Terminals,Headers, HCC Ametek Ind., New Bedford, MA USA Packages AuGe SolderHi-Rel Alloys, Ontario CA

As used herein, use of the term “control” with reference to the powersystem 16 generally relates to governing performance of the power system16. However, in some embodiments, “control” may be construed to providemonitoring of performance of the power supply. The monitoring may beuseful, for example, for otherwise controlling aspects of use of thepower supply (e.g., withdrawing the power supply when a state-of-chargeindicates useful charge has been expended). Accordingly, the terms“control,” “controlling” and the like should be construed broadly and ina manner that would cover such additional interpretations as may beintended or otherwise indicated.

In general, use of certain measures and components (such as the use ofthe wrapper 74, the washer 75, the encapsulant and the like) may providecertain prophylactic benefits and ensure performance of the power system16 in the harsh environment encountered downhole. Accordingly, whilesome of these measures and components may provide additional benefits,preparing the power system 16 for downhole operation by incorporation ofthese measures and components, where a prophylactic benefit is realized,may be, in at least some contexts, referred to as “hardening” of thepower system 16.

Some of the advantages of the power system 16 provided herein include anincreased level of safety provided by, for example, use of low ormoderate rate batteries where high rate batteries used to be necessary.The energy storage 30 does not contain substantial quantities of lead orlithium. The power system 16 includes extension of useable battery lifeby limiting temporary voltage dips normally seen during high currentdraw. Further, the power supply adds flexibility with inherent powerconversion so batteries may be more easily interfaced with tools andinstruments downhole. In addition, the power system 16 may provide boostpower while smoothing and limiting battery current draw usinghigh-temperature rechargeable ultracapacitors. These effects willgenerally extend usable life of batteries included in the power system16.

The power system 16 may also eliminate effects of voltage variations ona direct current (DC) bus that may otherwise lead to issues such as“cross-talk” or unwanted coupling across signal wires, by reducinglarge, fast voltage deviations from electrical circuits with in thepower system 16.

Having presented many aspects of the power system 16 that includes arechargeable energy storage 30, various performance parameters of anexemplary embodiment are provided in Table II.

TABLE II Performance Parameters for an Exemplary Downhole Energy SupplyParameter Symbol Value Op. temperature range T −40° C. to +250° C.(approximate) Max. Input Voltage V_(in, max) +100 V Min. Input VoltageV_(in, min) +2.5 V Const. Output Voltage V_(out) Adjustable: +2.5 to+100 V System Peak Power P_(pk) 0.10 W to 10 MW Max Output CurrentI_(max) 100 mA to 400 A System Energy E 0.01 J to 100 MJ Number of CellsN 2 to 1,000 Diameter D 1 cm to 30 cm Length L 10 cm to 3 m SystemWeight W 10 g to 30 kg System Volume V 10 cc to 30 Liters LeakageCurrent I/L <1,000 mA/L over T

Note that in Table I, System peak power is calculated using the peakpower of each cell, V_(w) ²/(4R_(dc)), multiplied by the number of cellsin the system, N. The maximum output current is calculated by dividingpeak power by a nominal system voltage 20 V. System energy is calculatedusing the per cell energy, ½CV_(w) ²/3,600, multiplied by the number ofcells in the system, N.

Key features resulting from embodiments of the exemplary system includeoperating temperatures up to about two hundred and fifty degreesCelsius, with survival temperatures above this; substantial use ofnon-toxic components; customizable current regulation and safety currentlimit; customizable output voltage setting; redundant electronics;automatic battery de-passivation; bypass operation to ensure fail-safe;and hermetic construction as well as others.

Accordingly, the system is highly deployable in applications such asdownhole MWD and LWD including those where high power and pulsed powerare needed. Among other things, in oil and gas or geothermal exploration(“downhole”), examples of benefits include: improved primary batterylife downhole by reducing losses internal to a battery by coupling apower system to a primary battery and a load leading to “smoothed”battery current that creates less energy loss compared to “peaky”current due to the squared relationship between current and ohmic lossesin the effective series resistance internal to the primary battery; anincrease system burst power capability by coupling the power system to arelatively low power source (e.g., the external energy source 51) and aload, which results in an ability to provide bursts of relatively highpower from an energy storage and to recharge the energy storage over alonger timeframe; an mitigation of intermittency in some power sourcessuch as generators by coupling of the power system 16 to a relativelyintermittent source and a load.

Thus, the teachings herein result in a downhole system that can boostpower downhole and extend the hours of runtime from 20% to 40% or moreover conventional systems. Further, this can enable the use of low rateor moderate rate batteries instead of high rate, while providingenhanced reliability through placement of fail safe and redundancyfeatures to minimize the potential for failure downhole, which resultsin simplified surface operation.

It should be recognized that the teachings herein are merelyillustrative and are not limiting of the invention. Further, one skilledin the art will recognize that additional components, configurations,arrangements and the like may be realized while remaining within thescope of this invention. For example, a user might wish to withdraw theenergy storage 30 and have it remain topside in some evolutions, whilesupplying power to the logging instrument 10 via cabling, such as viathe wireline 8. Generally, design and/or applications of the powersystem 16 in a downhole environment, or otherwise, are limited only bythe needs of a system designer, manufacturer, operator and/or user anddemands presented in any particular situation.

Further, various other components may be included and called upon forproviding for aspects of the teachings herein. For example, anadditional power supply (e.g., at least one of a generator, a wireline,a remote supply and a chemical battery), cooling component, heatingcomponent, pressure retaining component, insulation, actuator, sensor,electrodes, transmitter, receiver, transceiver, antenna, controller,electrical unit or electromechanical unit may be included in support ofthe various aspects discussed herein or in support of other functionsbeyond this disclosure.

In general, the power system 16 may include one to a plurality of typesof power converters. Exemplary types of power converters include,without limitation, “buck,” “boost,” “buck-boost,” “flyback,” “forward,”“switched capacitor,” and other isolated versions of non-isolatedconverters (e.g., Cúk, buck-boost), as well as cascades of any suchconverters (e.g., buck+boost). The converters may also be DC-AC(inverters), AC-DC (rectifiers), AC-AC. Exemplary types of switchedcapacitor circuits include, without limitation, Marx type, laddernetworks, series-parallel, charge pumps and the like. In general,converters may be switched mode or linear regulating types ofconverters. Switched mode converters may include, transistors, diodes,silicon controlled rectifiers, or any other type of switch that isdeemed appropriate by the interested party.

When introducing elements of the present invention or the embodiment(s)thereof, the articles “a,” “an,” and “the” are intended to mean thatthere are one or more of the elements. Similarly, the adjective“another,” when used to introduce an element, is intended to mean one ormore elements. The terms “including” and “having” are intended to beinclusive such that there may be additional elements other than thelisted elements.

Where appropriate, technology may be presented herein as a “circuit,” a“module,” a “component,” and by other similar (generallyinterchangeable) terms. It should be recognized that the form of thetechnology presented is not limited by the embodiments discussed herein.That is, it should be recognized that many aspects, such as circuitry,may be implemented as machine executable instructions stored in machinereadable media (i.e., as software), and vice-versa. Accordingly, whereappropriate, circuits may be included, or may be displaced by capableprocessors and the like (and vice-versa).

Where used herein, the term “automatic” and similar terms should beconstrued as the performance of a process or technique that generallyproceeds, at least in part, unattended or without interaction, and maycontinue on an ongoing basis of a defined or undefined duration. Forexample, a control circuit or software may receive an input, andautomatically make control adjustments. Adjustments and other processes,controls or techniques may be performed on a “real-time” or“substantially real-time” basis. However, terminology relating to“real-time” should be construed as performance of the particularprocess, control or technique within a period of time that issatisfactory to meet the needs of a user, designer, manufacturer orother similarly interested party, and is not intended to be limited toinstantaneous response or performance.

In the present application a variety of variables are described,including but not limited to components (e.g. electrode materials,electrolytes, etc.), conditions (e.g., temperature, freedom from variousimpurities at various levels), and performance characteristics (e.g.,post-cycling capacity as compared with initial capacity, low leakagecurrent, etc.). It is to be understood that any combination of any ofthese variables can define an embodiment of the invention. E.g., thecombination of a particular electrode material, with a particularelectrolyte, under a particular temperature range and with impurity lessthan a particular amount, operating with post-cycling capacity andleakage current of particular values, where those variables are includedas possibilities but the specific combination might not be expresslystated, is an embodiment of the invention. Other combinations ofarticles, components, conditions, and/or methods can also bespecifically selected from among variables listed herein to define otherembodiments, as would be apparent to those of ordinary skill in the art.

It will be recognized that the various components or technologies mayprovide certain necessary or beneficial functionality or features.Accordingly, these functions and features as may be needed in support ofthe appended claims and variations thereof, are recognized as beinginherently included as a part of the teachings herein and a part of theinvention disclosed.

While the invention has been described with reference to exemplaryembodiments, it will be understood that various changes may be made andequivalents may be substituted for elements thereof without departingfrom the scope of the invention. In addition, many modifications will beappreciated to adapt a particular instrument, situation or material tothe teachings of the invention without departing from the essentialscope thereof. Therefore, it is intended that the invention not belimited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention but to be construed by theclaims appended herein.

1. A power system adapted for supplying power in a high temperatureenvironment, the power system comprising: a rechargeable energy storagethat is operable in a temperature range of between about minus fortydegrees Celsius and about two hundred and ten degrees Celsius coupled toa circuit for at least one of supplying power from the energy storageand charging the energy storage; wherein the energy storage isconfigured to store between about one one hundredth (0.01) of a jouleand about one hundred megajoules of energy, and to provide peak power ofbetween about one tenth (0.10) of a watt and about one hundredmegawatts, for at least two charge-discharge cycles.
 2. The power systemof claim 1, wherein the temperature range is between about seventydegrees Celsius and about two hundred degrees Celsius.
 3. The powersystem of claim 1, wherein the temperature range is between aboutseventy degrees Celsius and about one hundred seventy five degreesCelsius.
 4. The power system of claim 1, wherein the temperature rangeis between about seventy degrees Celsius and about one hundred and fiftydegrees Celsius.
 5. The power system of claim 1, wherein the temperaturerange is between about seventy degrees Celsius and about one hundred andtwenty five degrees Celsius.
 6. The power system of claim 1, wherein thetemperature range is between about eighty degrees Celsius and about twohundred and ten degrees Celsius.
 7. The power system of claim 1, whereinthe temperature range is between about ninety degrees Celsius and abouttwo hundred and ten degrees Celsius.
 8. The power system of claim 1,wherein the temperature range is between about one hundred degreesCelsius and about two hundred and ten degrees Celsius.
 9. The powersystem of claim 1, wherein the temperature range is between about onehundred twenty five degrees Celsius and about two hundred and tendegrees Celsius.
 10. The power system of claim 1, wherein thetemperature range is between about one hundred twenty six degreesCelsius and about two hundred and ten degrees Celsius.
 11. The powersystem of claim 1, wherein the temperature range is between about onehundred fifty degrees Celsius and about two hundred and ten degreesCelsius.
 12. The power system of claim 1, wherein the energy storage isconfigured to store between about one tenth (0.1) of a joule and aboutone hundred megajoules of energy.
 13. The power system of claim 1,wherein the energy storage is configured to store between about onejoule and about one hundred megajoules of energy.
 14. The power systemof claim 1, wherein the energy storage is configured to store betweenabout ten joules and about one hundred megajoules of energy.
 15. Thepower system of claim 1, wherein the energy storage is configured tostore between about one hundred joules and about one hundred megajoulesof energy.
 16. The power system of claim 1, wherein the energy storageis configured to store between about one thousand joules and about onehundred megajoules of energy.
 17. The power system of claim 1, whereinthe energy storage is configured to store between about one onehundredth (0.01) of a joule and about ten megajoules of energy.
 18. Thepower system of claim 1, wherein the energy storage is configured tostore between about one one hundredth (0.01) of a joule and about onemegajoule of energy.
 19. The power system of claim 1, wherein the energystorage is configured to store between about one one hundredth (0.01) ofa joule and about one hundred thousand joules of energy.
 20. The powersystem of claim 1, wherein the energy storage is configured to storebetween about one one hundredth (0.01) of a joule and about ten thousandjoules of energy.
 21. The power system of claim 1, wherein the energystorage is configured to provide peak power of between about one tenth(0.10) of a watt and about one hundred megawatts.
 22. The power systemof claim 1, wherein the energy storage is configured to provide peakpower of between about one watt and about one hundred megawatts.
 23. Thepower system of claim 1, wherein the energy storage is configured toprovide peak power of between about ten watts and about one hundredmegawatts.
 24. The power system of claim 1, wherein the energy storageis configured to provide peak power of between about one hundred wattsand about one hundred megawatts.
 25. The power system of claim 1,wherein the energy storage is configured to provide peak power ofbetween about one one hundredth (0.01) of a watt and about tenmegawatts.
 26. The power system of claim 1, wherein the energy storageis configured to provide peak power of between about one tenth (0.10) ofa watt and about one megawatt.
 27. The power system of claim 1, whereinthe energy storage is configured to provide peak power of between aboutone tenth (0.10) of a watt and about five hundred thousand watts. 28.The power system of claim 1, wherein the energy storage is configured toprovide peak power of between about one tenth (0.10) of a watt and aboutone hundred thousand watts.
 29. The power system of claim 1, wherein theenergy storage is configured to provide peak power of between about onetenth (0.10) of a watt and about ten thousand watts.
 30. The powersystem of claim 1, wherein the energy storage is configured to chargeand discharge for at least 10 cycles.
 31. The power system of claim 1,wherein the energy storage is configured to charge and discharge for atleast 100 cycles.
 32. The power system of claim 1, wherein the energystorage is configured to charge and discharge for at least 1,000 cycles.33. The power system of claim 1, wherein the energy storage isconfigured to charge and discharge for at least 10,000 cycles.
 34. Thepower system of claim 1, wherein the energy storage comprises at leastone of a battery and an ultracapacitor.
 35. The power system of claim34, wherein the ultracapacitor is an electrochemical double layercapacitor that comprises at least one electrode comprising carbon energystorage media.
 36. The power system of claim 1, wherein the energystorage comprises an appearance that is one of cylindrical, annular,ring-shaped, flat, prismatic, stacked, box-like, and flat prismatic. 37.The power system of claim 1, wherein the power system is configured tosupply power to a logging instrument.
 38. The power supply of claim 37,wherein the logging instrument comprises at least one of a coring tool,a shut-in tool, a nuclear magnetic resonance imaging (NMR) tool, anelectromagnetic (EM) telemetry tool, a mud-pulser telemetry tool, aresistivity measuring tool, a gamma sensing tool, a pressure sensortool, an acoustic sensor tool, a seismic tool, a nuclear tool, a pulsedneutron tool, a formation sampling tool and an induction tool.
 39. Thepower system of claim 1, wherein a load comprises at least one ofelectronic circuitry, a transformer, an amplifier, a servo, a processor,data storage, a pump, a motor, a sensor, a thermally tunable sensor, anoptical sensor, a transducer, a light source, a scintillator, a pulser,a hydraulic actuator, an antenna, a single channel analyzer, amulti-channel analyzer, a radiation detector, an accelerometer and amagnetometer.
 40. The power system of claim 1, wherein the circuitcomprises at least one of: a processor, a power converter, a transistor,an inductor, a capacitor, a switch, a data storage and a bus.
 41. Thepower system of claim 40, further comprising machine executableinstructions stored in the data storage for execution by the processor.42. The power system of claim 1, further comprising an interface forcoupling to an external energy supply.
 43. The power system of claim 42,wherein the external energy supply comprises at least one of aconnection provided via wireline; a generator; a battery and anultracapacitor.
 44. The power system of claim 1, wherein the circuit isfurther configured to draw power from a plurality of types of energystorage devices.
 45. The power system of claim 1, wherein the circuitcomprises a circuit for at least one of: simulating an electricalsignal; monitoring a state of charge of the energy storage; governingchange-over from a first type of energy storage to a second type ofenergy storage; changing modes of operation; monitoring system health;storing and retrieving data; automatically adjusting an output voltage;entering a sleep mode; entering a state of low-power operation; andbypassing at least one component of the power system.
 46. The powersystem of claim 1, wherein the circuit is further configured formonitoring at least one of temperature, vibration, shock, voltage andcurrent.
 47. The power system of claim 1, wherein the circuit comprisesat least one redundant component.
 48. A method for providing power to alogging instrument downhole, the method comprising: selecting a logginginstrument that comprises a power system comprising a rechargeableenergy storage that is operable in a temperature range of between aboutminus forty degrees Celsius and two hundred and ten degrees Celsiuscoupled to a circuit for at least one of supplying power from the energystorage and charging the energy storage; and with the logging instrumentdownhole, providing power from the power system to the logginginstrument.
 49. The method of claim 48, further comprising charging thepower system with energy from an external energy supply.
 50. The methodof claim 49, wherein charging comprises at least one of continuously andperiodically charging the power system.
 51. The method of claim 48,further comprising: determining a failed state for a component of thepower system; and routing power from the energy storage around thefailed component.
 52. The method of claim 48, further comprisingcontrolling the providing to limit a duty cycle of the tool.
 53. Themethod of claim 48, further comprising regulating at least one of avoltage and a current delivered to the logging instrument.
 54. Themethod of claim 48, further comprising depassivating at least onebattery in the energy storage.
 55. The method of claim 48, whereinproviding power comprises drawing power from the energy storage andsimulating an electrical signal of another type of energy storage. 56.The method of claim 48, wherein providing power comprises monitoring astate of charge of the energy storage.
 57. The method of claim 48,wherein providing power comprises changing between types of energystorage.
 58. The method of claim 48, wherein providing power comprisesmonitoring at least one aspect of the power system and automaticallyadjusting an output of the energy storage.
 59. The method of claim 48,wherein providing power comprises monitoring at least one aspect of thepower system and at least one of activating a component of the powersystem and deactivating the component.
 60. The method of claim 48,further comprising monitoring data for at least one aspect of the powersystem and logging the data in memory.
 61. The method of claim 60,further comprising communicating the data to topside equipment.
 62. Amethod for fabricating a power system for a logging instrument, themethod comprising: selecting a rechargeable energy storage that isoperable in a temperature range of between about minus forty degreesCelsius and two hundred and ten degrees Celsius coupled to a circuit forat least one of supplying power from the energy storage and charging theenergy storage; and configuring the energy storage for incorporationinto the logging instrument.
 63. The method as in claim 62, furthercomprising assembling the energy storage from a plurality of storagecells.
 64. The method as in claim 63, wherein at least one insulator isdisposed between storage cells in the plurality.
 65. The method as inclaim 63, wherein at least one storage cell in the energy storage is atleast partially wrapped in a wrapper.
 66. The method as in claim 62,further comprising configuring the circuit for incorporation into thelogging instrument.
 67. The method as in claim 66, wherein configuringthe circuit comprises orienting the circuit to reduce at least one ofstress and strain experienced during operation.
 68. The method as inclaim 66, wherein configuring the circuit comprises assembling aplurality of circuit modules.
 69. The method as in claim 68, whereinassembling comprises selecting each of the modules according to at leastone feature provided by the respective module.
 70. The method as inclaim 68, wherein assembling comprises coupling each of the modules to abus.
 71. The method as in claim 68, wherein assembling comprisesdisposing a stand-off support between each of the modules.
 72. Themethod as in claim 68, wherein assembling comprises coupling a connectorof a first module with a mateable connector of a second module.
 73. Themethod as in claim 62, further comprising encapsulating componentswithin the power system with an encapsulant.
 74. The method as in claim62, wherein the circuit comprises at least one of: a power converter, avoltage regulating circuit, a low power consumption circuit, a bypasscircuit, a battery conditioning circuit and a current limiting circuit.75. A power system adapted for supplying power in a high temperatureenvironment, the power system comprising: at least one ultracapacitorthat is operable in a temperature range of between about minus fortydegrees Celsius and two hundred and ten degrees Celsius coupled to acircuit for at least one of supplying power from the ultracapacitor andcharging the ultracapacitor.
 76. The power system of claim 75, whereinthe ultracapacitor comprises at least one electrode comprisingcarbon-based energy storage media.
 77. The power system of claim 76,wherein the carbon-based energy storage media comprises at least one ofactivated carbon, carbon fibers, rayon, graphene, aerogel, carbon cloth,carbon nanotubes and another nano-form of carbon.
 78. The power systemof claim 75, wherein the ultracapacitor comprises an electrolyte. 79.The power system of claim 78, wherein the electrolyte comprises one of:less than 500 ppm of moisture, less than 1,000 ppm total concentrationof halides and less than 2,000 ppm total concentration of metallicspecies comprising at least one of Br, Cd, Co, Cr, Cu, Fe, K, Li, Mo,Na, Ni, Pb, Zn, at least one alloy of the foregoing metallic species, atleast one oxide of the foregoing metallic species.
 80. The power systemof claim 79, wherein the ultracapacitor is characterized by exhibiting aleakage current of no more than 1,000 mA/liter over the temperaturerange.
 81. The power system of claim 78, wherein the electrolytecomprises a plurality of cations, the cations comprising at least one of1-(3-cyanopropyl)-3-methylimidazolium, 1,2-dimethyl-3-propylimidazolium,1,3-bis(3-cyanopropyl)imidazolium, 1,3-diethoxyimidazolium,1-butyl-1-methylpiperidinium, 1-butyl-2,3-dimethylimidazolium,1-butyl-3-methylpyrrolidinium, 1-butyl-4-methylpyridinium,1-butylpyridinium, 1-decyl-3-methylimidazolium,1-ethyl-3-methylimidazolium and 3-methyl-1-propylpyridinium.
 82. Thepower system of claim 75, wherein the ultracapacitor comprises anelectrolyte, the electrolyte comprising a plurality of anions, theanions comprising at least one of bis(trifluoromethanesulfonate)imide,tris(trifluoromethanesulfonate)methide, dicyanamide, tetrafluoroborate,hexafluorophosphate, trifluoromethanesulfonate,bis(pentafluoroethanesulfonate)imide, thiocyanate,trifluoro(trifluoromethyl)borate.
 83. The power system of claim 75,wherein the ultracapacitor comprises an electrolyte, the electrolytecomprising a solvent, the solvent comprising at least one ofacetonitrile, amides, benzonitrile, butyrolactone, cyclic ether, dibutylcarbonate, diethyl carbonate, diethylether, dimethoxyethane, dimethylcarbonate, dimethylformamide, dimethylsulfone, dioxane, dioxolane, ethylformate, ethylene carbonate, ethylmethyl carbonate, lactone, linearether, methyl formate, methyl propionate, methyltetrahydrofuran,nitrile, nitrobenzene, nitromethane, n-methylpyrrolidone, propylenecarbonate, sulfolane, sulfone, tetrahydrofuran, tetramethylene sulfone,thiophene, ethylene glycol, diethylene glycol, triethylene glycol,polyethylene glycols, carbonic acid ester, γ-butyrolactone, nitrile andtricyanohexane.
 84. The power system of claim 75, wherein theultracapacitor is contained within a hermetically sealed container. 85.The power system of claim 84, wherein the hermetically sealed containercomprises aluminum.
 86. A power system adapted for supplying power in ahigh temperature environment, the power system comprising: arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit comprises a subsystem for depassivation of a battery in theenergy storage.
 87. The power system of claim 86, wherein the energystorage is configured to store between about one one hundredth (0.01) ofa joule and about one hundred megajoules of energy, and to provide peakpower of between about one tenth (0.10) of a watt and about one hundredmegawatts, for at least two charge-discharge cycles.
 88. The powersystem of claim 86, wherein the subsystem is configured to draw aconstant load from the battery for a period of time.
 89. The powersystem of claim 86, wherein the subsystem comprises measurementapparatus to assess a need for depassivation.
 90. The power system ofclaim 89, wherein the measurement apparatus comprises at least one of avoltage sensor and a current sensor.
 91. The power system of claim 89,wherein the measurement apparatus is configured to draw a predetermineddepassivating load current and monitor voltage of the battery until thevoltage rises to a predetermined level.
 92. The power system of claim91, wherein the measurement apparatus is configured to draw apredetermined depassivating load current and monitor voltage of thebattery until the voltage rises to a predetermined level.
 93. A powersystem adapted for supplying power in a high temperature environment,the power system comprising: a rechargeable energy storage that isoperable in a temperature range of between about minus forty degreesCelsius and two hundred and ten degrees Celsius coupled to a circuit forat least one of supplying power from the energy storage and charging theenergy storage; wherein the circuit comprises a subsystem for bypassinga component of the power system.
 94. The power system of claim 93,wherein the energy storage is configured to store between about one onehundredth (0.01) of a joule and about one hundred megajoules of energy,and to provide peak power of between about one tenth (0.10) of a wattand about one hundred megawatts, for at least two charge-dischargecycles.
 95. The power system of claim 93, wherein the subsystem isconfigured to automatically determine a failed state of a component andidentify an alternative current path from the energy storage to a load.96. The power system of claim 93, wherein the subsystem is disabled byproper functioning of components subject to the bypass.
 97. The powersystem of claim 93, wherein the subsystem includes at least onesolid-state device.
 98. The power system of claim 93, wherein thesolid-state device is a JFET.
 99. The power system of claim 93, whereinthe subsystem includes a relay.
 100. The power system of claim 93,wherein the subsystem includes at least one of a separate powerconverter and a redundant power converter.
 101. The power system ofclaim 93, wherein the subsystem includes a switch network to blockcurrent flow in at least one of into and out of a component that isbypassed.
 102. The power system of claim 101, wherein the switch networkincludes at least one of a diode and a transistor.
 103. A power systemadapted for supplying power in a high temperature environment, the powersystem comprising: a rechargeable energy storage that is operable in atemperature range of between about minus forty Celsius and two hundredand ten degrees Celsius coupled to a circuit for at least one ofsupplying power from the energy storage and charging the energy storage;wherein the circuit comprises a subsystem for simulating electricaloutput of an energy supply.
 104. The power system of claim 103, whereinthe energy storage is configured to store between about one onehundredth (0.01) of a joule and about one hundred megajoules of energy,and to provide peak power of between about one tenth (0.10) of a wattand about one hundred megawatts, for at least two charge-dischargecycles.
 105. The power system of claim 103, wherein the subsystemincludes a simulator map.
 106. The power system of claim 105, whereinthe simulator map is implemented in at least one of a digital domain andan analog domain.
 107. The power system of claim 103, wherein thesubsystem includes a feedback controller.
 108. The power system of claim107, wherein the feedback controller is implemented in at least one of adigital domain and an analog domain.
 109. The power system of claim 103,wherein the subsystem is configured for connecting in parallel with aload.
 110. The power system of claim 103, wherein the subsystem isconfigured for connecting in series with a load.
 111. The power systemof claim 103, wherein the subsystem includes at least one of a buckconverter, a boost converter, a buck-boost converter, a Cúk, flybackconverter and a forward converter.
 112. The power system of claim 103,wherein the subsystem supports bi-directional flow of power.
 113. Thepower system of claim 103, wherein an output of the simulator comprisesat least one of a voltage, a current, a power and an impedance.
 114. Thepower system of claim 103, wherein an input to the simulator comprisesis at least one of a voltage, a current, a power and an impedance. 115.A power system adapted for supplying power in a high temperatureenvironment, the power system comprising: a rechargeable energy storagethat is operable in a temperature range of between about minus fortydegrees Celsius and two hundred and ten degrees Celsius coupled to acircuit for at least one of supplying power from the energy storage andcharging the energy storage; wherein the circuit comprises a subsystemfor monitoring a state of charge of the energy storage.
 116. The powersystem of claim 115, wherein the energy storage is configured to storebetween about one one hundredth (0.01) of a joule and about one hundredmegajoules of energy, and to provide peak power of between about onetenth (0.10) of a watt and about one hundred megawatts, for at least twocharge-discharge cycles.
 117. The power system of claim 115, wherein thesubsystem includes a sense resistor for converting a current to avoltage.
 118. The power system of claim 115, wherein the subsystemincludes a hall effect sensor.
 119. The power system of claim 115,wherein the subsystem includes an inductive current sensor.
 120. Thepower system of claim 115, wherein the subsystem includes an analog todigital converter.
 121. The power system of claim 115, wherein thesubsystem includes a microprocessor.
 122. The power system of claim 115,wherein the subsystem includes a memory.
 123. The subsystem of claim122, wherein a variable in the memory is updated to reflect the state ofcharge.
 124. A power system adapted for supplying power in a hightemperature environment, the power system comprising: a rechargeableenergy storage that is operable in a temperature range of between aboutminus forty degrees Celsius and two hundred and ten degrees Celsiuscoupled to a circuit for at least one of supplying power from the energystorage and charging the energy storage; wherein the circuit comprises asubsystem for switching among at least two sources of energy.
 125. Thepower system of claim 124, wherein the energy storage is configured tostore between about one one hundredth (0.01) of a joule and about onehundred megajoules of energy, and to provide peak power of between aboutone tenth (0.10) of a watt and about one hundred megawatts, for at leasttwo charge-discharge cycles.
 126. The power system of claim 124, whereinat least one of the energy sources comprises at least one battery. 127.The power system of claim 124, wherein at least one of the energysources comprises a wireline coupled to a remote power supply.
 128. Thepower system of claim 124, wherein at least one of the energy sourcescomprises a generator.
 129. The power system of claim 124, wherein atleast two of the energy sources are a substantially similar type ofenergy source.
 130. The power system of claim 124, wherein at least twoof the energy sources are a substantially dissimilar type of energysource.
 131. The power system of claim 124, wherein the subsystem isconfigured to draw power from one energy source at a time.
 132. Thepower system of claim 124, wherein the subsystem is configured tosimultaneously draw power from at least one energy source.
 133. Thepower system of claim 124, where in the subsystem includes at least onetransistor.
 134. The power system of claim 124, where in the subsystemincludes a relay.
 135. The power system of claim 124, wherein thesubsystem includes a level shift circuit.
 136. The power system of claim124, wherein the subsystem modulates between energy sources to achieve atime-average aggregate behavior.
 137. The power system of claim 124,wherein the subsystem is configured to provide a digital changeovercontrol signal.
 138. The power system of claim 124, wherein thesubsystem is configured to provide an analog changeover control signal.139. The power system of claim 124, wherein the subsystem is configuredto interpret at least one of a state of charge of an energy source, avoltage presented by an energy source, an impedance presented by anenergy source, an ambient temperature, vibration, and a signal receivedfrom a remote location. and to provide a corresponding changeovercontrol signal.
 140. A power system adapted for supplying power in ahigh temperature environment, the power system comprising: arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit comprises a subsystem for automatically adjusting a voltageoutput of the power system.
 141. The power system of claim 140, whereinthe energy storage is configured to store between about one onehundredth (0.01) of a joule and about one hundred megajoules of energy,and to provide peak power of between about one tenth (0.10) of a wattand about one hundred megawatts, for at least two charge-dischargecycles.
 142. The power system of claim 141, wherein the subsystem isconfigured to control a voltage output according to temperature. 143.The power system of claim 141, wherein the subsystem is configured tocontrol a voltage output by providing a variable voltage set point. 144.A power system adapted for supplying power in a high temperatureenvironment, the power system comprising: a rechargeable energy storagethat is operable in a temperature range of between about minus fortydegrees Celsius and two hundred and ten degrees Celsius coupled to acircuit for at least one of supplying power from the energy storage andcharging the energy storage; wherein the circuit comprises a subsystemfor switching between modes of operation.
 145. The power system of claim144, wherein the energy storage is configured to store between about oneone hundredth (0.01) of a joule and about one hundred megajoules ofenergy, and to provide peak power of between about one watt and onemegawatt, for at least two charge-discharge cycles.
 146. The powersystem of claim 144, wherein the subsystem is configured to provide atleast two modes of operation.
 147. The power system of claim 144,wherein the subsystem is configured to provide for control of a voltageoutput from the power system.
 148. The power system of claim 144,wherein the subsystem is configured to provide for control of a currentoutput from the power system.
 149. The power system of claim 144,wherein the subsystem is configured to provide for control of a maximumcurrent output from the power system.
 150. The power system of claim144, wherein the subsystem is configured to provide for control of avoltage input to the power system.
 151. The power system of claim 144,wherein the subsystem is configured to provide for control of a currentinput to the power system.
 152. The power system of claim 144, whereinthe subsystem is configured to provide for control of a maximum currentinput to the power system.
 153. The power system of claim 144, whereinthe subsystem is configured to provide for deactivation of a circuit.154. The power system of claim 144, wherein the subsystem is configuredfor automatic operation.
 155. The power system of claim 144, wherein thesubsystem is arranged to be configured by way of a remote signal. 156.The power system of claim 144, wherein the subsystem is arranged to beconfigured by way of a user-generated signal.
 157. The power system ofclaim 144, wherein the subsystem for switching between modes ofoperation is configured according to temperature.
 158. The power systemof claim 144, wherein the subsystem for switching between modes ofoperation includes at least one transistor or relay for switchingpassive components.
 159. The power system of claim 144, wherein thesubsystem for switching between modes of operation adjusts a parameterin a digital controller.
 160. A power system adapted for supplying powerin a high temperature environment, the power system comprising: arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit comprises a subsystem for adjusting operation according to anenvironmental factor.
 161. The power system of claim 160, wherein theenergy storage is configured to store between about one one hundredth(0.01) of a joule and about one hundred megajoules of energy, and toprovide peak power of between about one tenth (0.10) of a watt and aboutone hundred megawatts, for at least two charge-discharge cycles. 162.The power system of claim 160, wherein the subsystem is configured toprovide for limiting a current input to the power system.
 163. The powersystem of claim 160, wherein the subsystem is configured to provide forlimiting a current output from the power system.
 164. The power systemof claim 160, wherein the subsystem is configured to provide forlimiting a voltage output from the power system.
 165. The power systemof claim 160, wherein the subsystem is configured to provide for controlaccording to temperature.
 166. The power system of claim 160, whereinthe subsystem is configured to provide for control according vibration.167. The power system of claim 160, wherein the subsystem is configuredto provide for control according to pressure.
 168. A power systemadapted for supplying power in a high temperature environment, the powersystem comprising: a rechargeable energy storage that is operable in atemperature range of between about minus forty degrees Celsius and twohundred and ten degrees Celsius coupled to a circuit for at least one ofsupplying power from the energy storage and charging the energy storage;wherein the circuit comprises a subsystem for inducing low-poweroperation.
 169. The power system of claim 168, wherein the energystorage is configured to store between about one one hundredth (0.01) ofa joule and about one hundred megajoules of energy, and to provide peakpower of between about one tenth (0.10) of a watt and about one hundredmegawatts, for at least two charge-discharge cycles.
 170. The powersystem of claim 168, wherein the subsystem is configured to be activatedduring preparation for at least one of storage and transport.
 171. Thepower system of claim 168, wherein the subsystem is configured to beactivated by installation of a cover.
 172. The power system of claim171, wherein the subsystem is configured to cause a short circuit acrossat least two pins of one of a digital controller and an analogcontroller when the cover is installed.
 173. The power system of claim168, wherein the subsystem is configured to be activated by installationof a cover comprising a resistor.
 174. The power system of claim 168,wherein the subsystem is configured to be activated by installation of acover comprising a battery.
 175. The power system of claim 168, whereinthe subsystem is configured to be activated by installation of a covercomprising a diode.
 176. The power system of claim 168, wherein thesubsystem comprises a dustcap with a rotatable connector.
 177. The powersystem of claim 168, wherein the subsystem is configured to be activatedby detection of non-operation.
 178. The power system of claim 177, wherein the detection of non-operation is indicated by a period of lowcurrent output.
 179. The power system of claim 168, wherein thesubsystem is configured to provide for disabling of at least onecomponent.
 180. The power system of claim 168, wherein the subsystem isconfigured to provide for controlling a voltage output.
 181. A powersystem adapted for supplying power in a high temperature environment,the power system comprising: a rechargeable energy storage that isoperable in a temperature range of between about minus forty degreesCelsius and two hundred and ten degrees Celsius coupled to a circuit forat least one of supplying power from the energy storage and charging theenergy storage; wherein the circuit comprises a subsystem for loggingdata.
 182. The power system of claim 181, wherein the energy storage isconfigured to store between about one one hundredth (0.01) of a jouleand about one hundred megajoules of energy, and to provide peak power ofbetween about one tenth (0.10) of a watt and about one hundredmegawatts, for at least two charge-discharge cycles.
 183. The powersystem of claim 181, wherein the subsystem for logging data includes amemory.
 184. The power system of claim 181, wherein the subsystem isconfigured to provide at least one of controlling system operation,sending a status to a remote location, and assessment of the powersystem after operation.
 185. The power system of claim 181, wherein thesubsystem is configured to record at least one of a battery voltage, abattery current, a battery state of charge, temperature, vibration, ashock events, and a logic event.
 186. The power system of claim 185,wherein the logic event comprises an indication of at least one of fluidflow, mud pulse actuation, and changeover state.
 187. The power systemof claim 181, wherein the subsystem is configured to retrieve data frommemory.
 188. The power system of claim 181, wherein the subsystem isconfigured to communicate data.
 189. The power system of claim 181,wherein the subsystem comprises read-only-memory.
 190. The power systemof claim 181, wherein the subsystem comprises random-access-memory. 191.The power system of claim 181, wherein the subsystem includes aplurality of memory chips.
 192. The power system of claim 181, whereinthe subsystem is configured to provide for archiving data stored in alocation in RAM to a location in ROM.
 193. The power system of claim181, wherein the subsystem is configured to provide for storingparameterized data.
 194. A power system adapted for supplying power in ahigh temperature environment, the power system comprising: arechargeable energy storage that is operable in a temperature range ofbetween about minus forty degrees Celsius and two hundred and tendegrees Celsius coupled to a circuit for at least one of supplying powerfrom the energy storage and charging the energy storage; wherein thecircuit comprises a subsystem for managing performance of the powersupply.
 195. The power system of claim 194, wherein the energy storageis configured to store between about one one hundredth (0.01) of a jouleand about one hundred megajoules of energy, and to provide peak power ofbetween about one tenth (0.10) of a watt and about one hundredmegawatts, for at least two charge-discharge cycles.
 196. The powersystem of claim 194, wherein the subsystem is configured to provide forrun-time adjustment.
 197. The power system of claim 194, wherein thesubsystem is configured to provide for periodic adjustment.
 198. Thepower system of claim 194, wherein the subsystem is configured toprovide for adjustment by a user.
 199. The power system of claim 194,wherein the subsystem is configured to provide for adjustment activatedby a remote signal.
 200. The power system of claim 194, whereinminimizing power loss is aided by at least one of a first computation ofestimated power loss, measurement of at least one electrical parameter,iterative perturbation and observation steps, and iterativecomputations.
 201. The power system of claim 194, wherein the subsystemis configured to provide for minimizing at least one of standby powerloss, self-discharge power loss, transistor switching and gating loss,conduction loss and core loss.
 202. The power system of claim 194,wherein the subsystem is configured to provide for minimizing power lossin a load.
 203. The power system of claim 194, wherein the subsystem isconfigured to control at least one of a voltage output from the powersystem, a current output from the power system, and a power output fromthe system.
 204. The power system of claim 194, wherein the subsystem isconfigured to adjust a control signal.
 205. A power system adapted forsupplying power in a high temperature environment, the power systemcomprising: a rechargeable energy storage that is operable in atemperature range of between about minus forty degrees Celsius and twohundred and ten degrees Celsius coupled to a circuit for at least one ofsupplying power from the energy storage and charging the energy storage;wherein the circuit comprises a subsystem for monitoring health of thepower system.
 206. The power system of claim 205, wherein the energystorage is configured to store between about one one hundredth (0.01) ofa joule and about one hundred megajoules of energy, and to provide peakpower of between about one tenth (0.10) of a watt and about one hundredmegawatts, for at least two charge-discharge cycles.
 207. The powersystem of claim 205, wherein the subsystem includes a memory.
 208. Thepower system of claim 205, wherein the subsystem includes at least oneof a temperature measuring device and an acceleration measuring device.209. The power system of claim 205, wherein the subsystem is configuredto derive an estimate of system health from a measurement of at leastone of temperature, vibration and shock.
 210. A power system adapted forsupplying power in a high temperature environment, the power systemcomprising: a rechargeable energy storage that is operable in atemperature range of between about minus forty degrees Celsius and twohundred and ten degrees Celsius coupled to a circuit for at least one ofsupplying power from the energy storage and charging the energy storage;wherein the circuit comprises a subsystem for accessing redundantelements.
 211. The power system of claim 210, wherein the energy storageis configured to store between about one one hundredth (0.01) of a jouleand about one hundred megajoules of energy, and to provide peak power ofbetween about one tenth (0.10) of a watt and about one hundredmegawatts, for at least two charge-discharge cycles.
 212. The powersystem of claim 210, wherein the subsystem comprises at least onestandby rechargeable energy storage device.
 213. The power system ofclaim 210, wherein the subsystem comprises at least one standby circuit.214. The power system of claim 213, wherein the standby circuitcomprises a power converter.
 215. The power system of claim 210, whereinthe subsystem is configured to identify a fault from a voltage outputmeasurement.
 216. The power system of claim 210, wherein the subsystemis configured to identify a fault from a voltage output measurement forthe rechargeable energy storage and a current through the rechargeableenergy storage.
 217. The power system of claim 210, wherein thesubsystem comprises a plurality of resistor dividers coupled to aplurality of rechargeable energy storage devices and analog to digitalconverters.
 218. A method using a power supply, the method comprising:selecting a power supply that comprises at least one ultracapacitor; andoperating the power supply within a temperature range of between aboutminus forty degrees Celsius and about two hundred and ten degreesCelsius while maintaining a voltage of between about 0.1 Volts to about4 Volts on the ultracapacitor for at least one hour; wherein, at the endof the hour, the ultracapacitor exhibits a leakage current less than1,000 mAmp per liter of volume over the range of operating temperature.219. A method of using a power system, the method comprising: coupling arechargeable energy storage configured for high temperature operationwith electronics configured for high temperature operation; andoperating the power system by withdrawing pulses of power from an outputof the power system, wherein each pulses comprises a peak value of atleast 0.01 W and a total power-time product (energy) of at least 0.01 J.